When choosing the right wire size for lights and outlets, it is generally used to use 14-gauge wire for 15-amp light circuits and 12-gauge wire for 20-amp outlets. Factors such as voltage, wattage, distance, and environmental conditions play a significant role in determining the appropriate wire size. For hardwiring LED lighting fixtures, it is essential to select the right wire size and ampacity for your lighting needs to avoid voltage drop.
Indoor light fixtures should be determined based on circuit voltage, wattage, and ampacity. The American Wire Gauge (AWG) system provides a chart of voltage and wattage for different wire sizes and lengths, along with tips on wire protection and battery.
The size or gauge of the conductor is crucial when selecting the right wire size. Copper conductors can carry bigger current, and the larger the conductor, the more current it can safely carry. For powering electrical appliances, 10-gauge and 8-gauge are more common.
Common sizes include 16-, 14-, 12-, 10-, 8-, 6-, and 2-gauge wire. The size of the wire dictates how much current can safely pass through the wire. Electrically, 22AWG is suitable, but mechanically, a larger gauge (20 or 18) might be more suitable.
When selecting the right wire for your indoor or outdoor solar lighting setup, consider the voltage drop and ampacity of the wire. For most residential LED downlights and recessed lighting applications, a 12-2 cable is recommended. It is important to calculate the total amperage your circuit requires.
In summary, choosing the right wire size for lights and outlets depends on factors such as voltage, wattage, distance, and environmental conditions. By understanding the American Wire Gauge system and using the correct wire size chart, you can ensure the safety and efficiency of your lighting setup.
📹 Understanding Wire Gauges | Ask This Old House
In this video, This Old House master electrician Heath Eastman teaches host Kevin O’Connor about wire gauges and the …
What size wire for ceiling light?
16-gauge wire is suitable for light-duty extension cords and LED lighting circuits, supporting up to 13 amps. 14-gauge is used for light fixtures, lamps, and recessed lighting circuits with 15 amps, while 12-gauge is used in kitchens, bathrooms, outdoor receptacles, and 120-volt air conditioners. The 12-2 cable is the common option for most LED recessed lights systems, indicating a 12-gauge cable with two insulated conductor wires and a ground wire. However, it is important to consult state or city electrical codes for specific requirements on recessed ceilings.
What size wire for indoor wiring?
Modern home electrical systems typically use 12 or 14 gauge wires, with larger appliances like ovens, washers, and dryers having 10-, 8-, or 6-gauge wires. The smaller the AWG number, the thicker the wire. Knowing the proper wire gauge is crucial when extending electrical service, such as adding an outlet to a room. Loose change can be used to determine the size of wires, with a nickel being about the same size as 12-gauge wire for 20-amp circuits and a dime being about as thick as 14-gauge wire for 15-amp circuits.
What size wire do I need for LED lights?
To wire LED lights, use a wire gauge of 18 AWG or higher and a high-quality soldering iron and solder. A 24V DC power supply is required to power Hit Pro 24V LED strips. LED lights are popular due to their energy efficiency, durability, and versatility. To successfully install LED lights, follow these steps: Determine your power supply, connect your LED lights, and install them. Luma5 12V LED Strip Lights, COB Lighting 24V COB Lights, and Hit Pro 24V LED Strips are all options to consider. Ensure to have a clear understanding of the process and the right tools to ensure a successful installation.
Is 2.5 mm cable ok for lighting?
2. 5mm wire is suitable for lighting, but it is thicker, less flexible, and more expensive. Standard cables for domestic lighting are 1. 5mm. The size of cable depends on the number of lights in the loop. For LED lights with reduced power demands or low lights, 1. 5mm cables are acceptable. Lighting cable size UK recommends 1. 5mm cables for most lighting circuits. If fewer lights or LED bulbs are used, 1mm cables may be suitable.
How many watts can a 1.5 mm cable take?
The type of cable you need depends on the application and the power rating. The capacity of a cable to carry electricity depends on the cross-sectional area of the conductors, which are copper cores that conduct electricity. The cross-sectional area is measured in mm², and thicker cables with larger diameter cores can carry more electricity. In round cables, the cross-sectional area can be calculated using π. Cable is often rated by reference to current or power rather than conductor size.
Understanding these ratings involves three concepts: current (the flow of electrons in the cable) in Amps, voltage (the electrical pressure applied to the cable) in Volts, and power (the product of current and voltage) in Amps x Volts.
Can I use 2.5 mm cable for a fridge?
The 1. 5mm wire, rated at 10 amps maximum, is inadequate to supply the requisite power due to the substantial load on the refrigerator. The use of a thicker wire is therefore necessary. A 5 mm wire would be a more appropriate choice.
What diameter wire do I need for lighting?
2. 5mm wire is suitable for lighting, but it is thicker, less flexible, and more expensive. Standard cables for domestic lighting are 1. 5mm. The size of cable depends on the number of lights in the loop. For LED lights with reduced power demands or low lights, 1. 5mm cables are acceptable. Lighting cable size UK recommends 1. 5mm cables for most lighting circuits. If fewer lights or LED bulbs are used, 1mm cables may be suitable.
Is it okay to oversize electrical wire?
The installation of a larger amperage circuit is typically considered a safe procedure due to the reduction in voltage drop and the enhanced accessibility for future maintenance. Nevertheless, the financial outlay required for the purchase and installation of larger wires is greater, and there is no guarantee that the cost of undertaking the same task will be more economical.
What size wire is needed for LED lights?
To wire LED lights, use a wire gauge of 18 AWG or higher and a high-quality soldering iron and solder. A 24V DC power supply is required to power Hit Pro 24V LED strips. LED lights are popular due to their energy efficiency, durability, and versatility. To successfully install LED lights, follow these steps: Determine your power supply, connect your LED lights, and install them. Luma5 12V LED Strip Lights, COB Lighting 24V COB Lights, and Hit Pro 24V LED Strips are all options to consider. Ensure to have a clear understanding of the process and the right tools to ensure a successful installation.
What size cable for indoor lighting?
Lighting circuits are typically run in 1mm2 two-core-and-earth cable, with long circuits using 1. 5mm2 cable to compensate for voltage drops. Hall or landing lights are often controlled by two-way switching, using a junction box or loop-in rose to link a switch to a second one using special three-core-and-earth cable. If changes are made to a bathroom’s power or lighting circuit, local authorities must be notified and circuits must be protected by a 30mA RCD.
Can I use 1.5 mm cable for lighting?
Twin core and earth cabling is commonly used in homes in various sizes, with 2. 5mm for behind sockets and 1-1. 5mm for lights. Two-way lighting uses 3 core and earth connections between two switches. The cable consists of three solid cores, individually insulated and wrapped in an outer PVC sleeving. The colors of these cores are brown, black, and grey, with a bare earth core insulated with green and yellow sleeving. Steel Wired Armoured (SWA) cable is used for outside use to move power underground or overhead using a catenary wire.
📹 Electric Cable & Fuse Sizing – Camper Van Conversion Series
Download your FREE wiring diagrams here:- BS7671 Cable Sizing Chart …
Download your FREE wiring diagrams here:- BS7671 Cable Sizing Chart – dropbox.com/s/5lf55srgelpoclo/Cable%20Sizing%20Table.pdf?dl=0 Wiring Diagrams for different types of off-grid van systems are here:- The final wiring diagram from today’s masterclass article is on this link dropbox.com/s/meaa9brw2hxifei/How%20to%20wire%20your%20van.jpg?dl=0 1 solar panel, MPPT charge controller, 1 leisure battery and inverter. dropbox.com/s/1f5plerswoz7l2w/Off%20Grid%20Van%20Wiring.jpg?dl=0 1 solar panel, MPPT charge controller, 1 leisure battery and inverter. dropbox.com/s/evzci35h8etyi68/Van%20Wiring%20Schematic.jpg?dl=0 2 solar panels, MPPT charge controller, 2 leisure batteries and inverter. dropbox.com/s/h5yfuf090hgp4ga/Dual%20Solar%20and%20Battery%20Setup.jpg?dl=0 3 solar panels, MPPT charge controller, 3 leisure batteries and inverter. dropbox.com/s/92ubo6d6k9miotq/Greg%20Virgoe%20Van%20Wiring%20Schematic.jpg?dl=0
Greg, I can’t thank you enough for the content you create. I’m three weeks into a Ford transit conversion and have been consistently reassured and guided by the articles you share. You’ve helped me decide when I can do something myself, when to ask for help and when to consult a professional! Thank you so much and please keep creating and teaching 🙂
I’ve started to build my dream home on wheels. I’ve literally used a drill, saw and the like for the first time last week. I’m overwhelmed and terrified I’ve bitten off more than I can chew! Then I found your website. Thank you so very much for all your work. You are literally saving my life. I almost used cables that are too small AND not flexible. I’ve also learned from you that just cuz someone sounds good when they speak does not mean they really did any research. Thank you from the bottom of my heart.
My dad was an electrical engineer, I wish I had paid more attention to what he told me. I came across this article along with your water system, brilliant. I’ve just decided to upgrade my 43 year old Tabbert caravan, instead of spending a shed load of money buying a newer one that’s had a hard life. The parts all start arriving tomorrow, so your article has been gratefully received, thanks. I’m off to watch another of your vids.
Greg this just fantastic. I’ll probably never wire a van but if I do I know where to come. Something that has confused me for many many years is explained here quickly in a simple easy to understand manner with the addition of clear and concise graphics. Time consuming for you but so helpful for others. Stay well and hopefully we all can get back on the road very soon.
I really appreciate the fact that you take the time to explain this stuff. In particular the safety side, like not using solid core wire. This is overlooked very often. I wanted to add that when using multicore wires it is important to use the right connectors. Make sure they are rated for the correct current. But also that the stripped end of the wire is properly clamped in the connector. There should be no exposed copper (cores), as over time some of the cores can break and could fall out and cause a short. Use heat-shrink and or heat-shrink to prevent any cores from falling out. Especially in areas with sensors. At 11:20 you are right that this is not the proper way to wire it, however the explanation is not correct. Assuming all 8 lights are the same each light would have the same voltage potential across it. The first light would have 12V (with respect to ground) at the positive lead. The negative lead would be 10.5V (with respect to ground). So the voltage potential across the light would be 1.5V. This is the same for all the lights. Since the lights are wired in series, the current is also equal for each light. This means all the lights will be equal brightness. In the case of a regular light bulb all lights would be very dim, but the same brightness. When using LEDs (like in the example picture) the lights would probably not turn on at all, since leds are diodes that require a minimum voltage to operate.
This is absolutely brilliant. As someone who barely scraped an A-Level Physics 40 years ago and is now wishing I’d listened now closely (as I’m wiring my home solar/van system), I have to say that this is so well presented and explained that this should be a model for all such articles on YouTube! Greg explains this all so clearly and at such a great (medium) pace that it neither loses you (by going too fast) nor makes you fall asleep (too slow)! Also, no unnecessary background music! Great job greg – Thanks! -)
Nicely done Greg, I wonder how many vans have you to credit so far! Just one small point to correct, if you put several (equal) lamps in series they’ll divide the potential equally. As a result the first won’t be any brighter than the rest – they’ll all be equally dim! 12v ÷ 4 lamps 3v drop per lamp, i.e.1/4 of the12v required for full brightness.
Hi Greg I found this website today and have been glued to it for hours. I must congratulate you on these articles as your delivery and content is exceptional! So good that I leave the adverts running so you receive any money from them. Thank you so much for the articles, they have given me the confidence to try some. Please keep the articles coming as they are so good that they are on a par with Paul Sellers woodworking. I really can’t pay you any more of a compliment than that. Brand new subscriber as from today. Well done Sir.
Hi Greg, good information for all the busy lockdowners! Regarding the 230v side of things, remember BS7671 states that 230v circuits need overload protection that breaks all live conductors in a caravan or mobile home. I’m sure you know that on 230v the neutral is also a live conductor so that means double-pole mcb’s.. This means that your 230v distribution boards can get quite big as we usually have battery charge circuits, water heating and sometimes electric space heating for when hooked up. And watch out for rcbo’s as most are still single pole break operation, not double pole as required. Keep up the good work
Hello from Florida Greg. I’m an absolute neophyte who intends to re-wire a 1964 vintage runabout boat i recently purchased. It’s a simple enough job with only a few components: navigation lights, tachometer, USB ports, horn, and a gps/fishfinder. This article, though written for van owners (another project in my future), is spot-on what i needed to understand basic wiring. Now i just need to find a conversion chart which converts mm/2 wiring into “gauge” size, which we use here in the US. I also figured out an easy to remember hack for remembering the “power equation” which may be helpful to US viewers. Just think “West Virgina”….which is abbreviated W. VA. Voila, put the W on top, the VA on the bottom, and you have the power equation. Now, if i could just translate some of the British speak below… “no waffling”, “as it says on the tin”, “belting article” . You win my vote for “top man”!……..Cheers! (<---see what i did there?).
Great vid Greg, thank you. With any wiring installation, it’s sometimes hard to understand how much energy builds up within the cable when appliances are switched on. Your clip showing a wires heating and subsequently melt/combust shows what could potentially happen behind the insulation in a van. Therefore your visual demonstration and clear cabling sizing chart will enable us all to sleep safely. Cheers!
Hello mister greg, i am french sorry for my english. I want to say thank you verry mush. your articles is verry hepfull. In the other articles the guys are speed and nervous but you, you are quiet and peace it’s a pleasure to listen. The next month i will buy an crafter or jumper and the big work can start. Wish me good luck. 😁
As I am starting building my own van now, I have came across many articles here. Most of them sound and look like a dance party. Greg is practical and explains everything in details, diagrams, scientific explanation, formulas, etc. Well, some rock’n’roll from time to time won’t be wrong :). Greg – the van convertion professor! Thank you.
This is awesome content, and it’s given me some confidence that I can at least try to plan the electrics for my van conversion that I plan to start this year. I’ll obviously consult a professional, but having this as a guide is really useful. So glad I found it! You make it so easy to understand, top job!
Just. Brought a van to convert myself and electrics n plumbing a mine field for me – am ok on diy lol but your articles have explained clearly the wiring and i am confident enough to do it myself – and checked over by a electrician friend to be on safe side – thankyou i look forward to checking out all your articles on converting before i make a start ❤️
I hit subscribe at 2:06 when you talk about the importance of accurate information and your understanding of the consequences and responsibilty you take on by putting this information in the public domain. It is so refreshing to hear a youtuber who is aware of this factor and acts responsibly. Well done sir. You just got a very well earned sub 😉 And thank you for your great work.
I am currently in the planning stages of my first build; the power of it all is what has me so intimidated. I am so thankful for this article, you didn’t just say do this – use this, but rather took the time to explain why so we can easily adjust for our use. Your detailed explanation will also help us troubleshoot down the line if we run into issues or decide to add or upgrade a load.
This is, most probably the most useful pack of information on the electrics of a camper van excellently presented. I cannot thank you enough. There is however, just one aspect that contains an error: At the minute 11:31, If identical lights are connected in series, as theyare identical and they all have the same resistance, and as the same current (intensity) goes through all of them, (since they are in series) so the voltage drop across each light is exactly the same, and the power dropped on each lamp is the same so the brightness is the same so they will all be quite dim but just as dim as each other. But the conclusion is still 100% right: the lights and all the 12Vcomsumers should be wired in PARALLEL. I hope this helps. with best regards
Great info. The electrical is the only part of the build that intimidates me. Having a dedicated playlist for this is a great idea. Really interesting info about the difference in the current being within an insulated wall vs on the outside of the wall. My plan is to put the wiring outside of the wall so having this info is super helpful. Thanks so much!
Hi Greg.. You da man by the way😂. After perusal sooo many of your excellent vids I thought wouldn’t it be great if you did a upto date vid on electrics which includes lithium /Po4 batteries… If its a case of just swapping the old batteries for new ones then forgive my innocence 🤦. Keep up your amazing amazing work👌
Greg – I really like all your articles. I don’t believe you are correct between 11.28 and 11.38 in the above. I would have thought that the series wired lights would have had a similar voltage drop across them and therefore would have a similar brightness or (not work because of low voltage.) About to use your articles to help me wire my Citroen Relay. Thanks Again John.
Good practical advice… I have repair/total re-wired an old Land Rover far from civilization a couple times years ago with relieved and happy outcome years ago. And, my 1963 Airstream too using techniques as you clearly explain. But for good or bad, modern auto-electrics/electronics cannot afford other than to minimize as much as possible from power consumption to using smallest wire sizes possible, to the point of scary small and wimpy appearing. Now the trend has been for awhile in automotive wiring replacing electrical components like resistive lighting with chip based (LED) lighting getting for 100ma 5 times the light output of a 10 watt bulb, use of centralized microprocessor control of switching and fault protection solid state circuits, making hobby projects in some cases like with the mo.unit blue as sophisticated as factory systems… and very simple to wire and program. Though these require a more particular approach, but the result is simply amazing. A bike I bought with a butchered factory backyard modified electrical system I used one of these modern but not new technology units along with a mo.button digital control signal converter using one 24 gage wire and a ground to provide control inputs for all functions of the entire rather complicated electrical system… and my cell phone to program it. With hands off security protection and keyless start and stop.
Really enjoying your articles Greg. Just bought a L3H3 Sprinter and starting my strip-out now. As a complete novice one thing I would find really useful is if you went through how you run your cables and do your connections for something like a lighting run for example. Great work… Please keep up the fantastic work!
Dude, your articles are the absolute best. I’m just starting to get into designing my build for my van and every question I’ve had about electrical I’ve been able to get answer ed thank you so much for making everything so easy to understand making available all these diagrams. It is extremely helpful.
Legend, spending time lsitening to you and perusal your articles has been nothing but educational and allowing so many people to translate your advice into logical practical application, credit where it’s due. Britains godfather of van builds, thank you for putting an enormous amount of time and effort into filming, editing and publishing this information. I hope I don’t mess my install up now. lol Thanks Greg.
Hi Greg. First off thanks so much for all your articles on self build campers. I’ve been following your articles from the very beginning of my sprinter build, You’ve helped me out so much. My question is about what size of breaker should I be using from the leisure batteries to the fuse box. So far I’ve got a maxfan and some LED lighting coming from the box. Thanks for any advice in advance. BTW I’m owe you several pints for all your very detailed and informative articles.
Hi Greg, perusal all your article’s while on 14 day quarantine in China (I can’t even move outside my hotel room). One question on electrics….Do your use relays? Maybe I’m wrong I noticed some switches (on your charts) do not look so “robust”. Your articles are by far the most researched and thorough.
Hi Greg, I found you article while looking for fuse sizing to protect a couple of oven lights in a powder coating oven I have nearly finished building. It is 240V but I know that Watts Law applies just the same. Thank you for producing and sharing such useful content and in a very clear and easy to understand format. Brilliant work, I have just subscribed to your website. kind regards Paul
Hey…thanks for your articles. I pick your brain all the time for my new trailer conversion. So…I am planning an install of two 200W panels (Newpowa 200W Monocrystalline 200 Watt 12V Solar Panel High Efficiency Mono Module RV Marine Boat Off Grid (200W New)) on the roof of my new 6×10 trailer conversion. Each panel will have an inline fuse on the positive cable. I also have a portable set of panels (Dokio 300W kit), which I normally use to charge my portable Jackery 1000. I will be joining the two rooftop sets of wires from the panels into one set using a y-connector and then entering my trailer roof. Then in the electrical compartment, install another y-connector which would allow me to, on occasion, connect my portable panels to add to the system solar input. Would having that occasionally accessed ability screw up my solar inputs? I al also installing a switchable 30A circuit breaker on the positive feed from the solar panels. That would give me the ability to switch off the positive feed when I needed to work on the system. The system (mostly guided by your instruction) I am building in the next few days: Renogy 40A controller with Bluetooth, feeding a 100 Battleborn Lithium. The battery is also feeding the busses which feed a 12v fuse box, which feeds my trailer lighting, fridge, and stuff. There is a catastrophic 300A circuit breaker and then a battery switch between the battery and the positive Buss. The 12v fuse box is also fed by a converter (Progressive Dynamics PD9260CV Inteli-Power 9200 Series Converter/Charger with Charge Wizard – 60 Amp).
To echo the many comments again! Just how great your articles are Greg, Thank you! Apologies if I’ve missed your reply elsewhere, but I’m still keen to understand the question of earthing or more to the point not grounding to the chassis. So many folk say that its a must but you recommend not to ? It makes sense to me not to, but without a ground to chassis, I’m wondering whether that’s why I get a small shock sometimes from appliances run through my inverter….? As its part of my “leisure battery system” from what you are saying it also doesn’t need to be grounded beyond connecting the negative cable directly to the negative pole on my battery source, Is that correct ? or does the inverter actually need grounding to the chassis ? I understand that the vans electrical system is already grounded to the chassis and that its best to keep the leisure battery system separate, but i wonder why so many folk say that a good ground to chassis helps to avoid electric shocks etc. Thanks in advance 🙂
Hi Greg, Love your informative articles. Can i just ask your opinion? You dont mention volt drop along a length of cable. I believe as another layer we need to then compare to a volt drop table to possibly up the cables sizes. I know this is the case for the likes of a fridge as mine needs a massive cable. regards Rob
Thanks, this was very helpful! I was wondering if a USB adapter like this one uses 3.1 Amps on 5V while charging the connected devices instead of 3.1 Amps on 12V? 5V x 3.1A = 15.5W, that’s about 1.3A on 12V, so the fuse can be lower I guess, if you don’t consider the extra current possibly needed for the 12V-5V conversion and the heat this produces. I’m gonna put an Amps meter on it next weekend 🙂
Hi Greg, Thank you for your great article, so informative and well explained. This was a very daunting part of the process for me for both a van build and understanding better the electrical system on my narrowboat. I have been contemplating the electrical system and think that i have no real requirement for 240V as most things now can use 12v for and from the boat know that inverters use quite a lot of electric. Is there any reason why I can’t do this as all diagrams seem to include 240V? Also I am keen to understand more about how to charge the leisure batteries from the Alternator and the cabling etc required< do you cover this in your articles anywhere?
Greg, I really appreciated this article. Your willingness to share good information. Safe information. I am in the build process of a Toyota Tacoma for the purpose of dispersed camping. Out back the typical camp lighting, fridge, water. Up front the higher draw load items, bigger lights and winch. I’ve done a lot of work so far and have got to the aspects of the wiring. You make no mention of the use of relays in this article. I understand the principal use of a relay. Was there no need to mention a relay in this vid because the loads were small? If the switch carries good amperage rating is it okay to use just the switch? Thanks – William USA
Hi Joe Virgoe, Happy New Year. sending the best wishes all the way from America. I have followed all your electrical articles and charts. I have a request. Do you have an electrical diagram that shows how to do the electric distribution for a non-solar system, a regular generator, an inverter, and a way to connect to a house regular source? Thank you
Hi Greg. Your vids are so informative. I have a question about standard day van set ups. I know I require an in-line fuse from main battery to split charge relay, but do I need a further fuse from other side of split charge relay to the leisure battery. From the positive terminal of the leisure battery I’ll be adding a kill switch and then routing a cable onto a fuse box for all my positive connections to LEDs, USB etc and adding a ground negative block, but as I said, just wondering about a secondary inline fuse in-between split charge relay and leisure battery??? many thanks, Mark
I think, on the initial install of wiring, I would either add an additional wire set inside the conduit, leaving it unattached and taped off at both ends. That way, when and if I needed to add or fix some wiring, the wire is already inside the conduit. This could also be used for simple troubleshooting. Or, I’d lay a piece of string/rope/ inside the full length of any run on the initial install, and if more wires are needed later, I could attach them to the piece of string and pull through from other end. Do you see a problem with this plan? Thanks.
Hey Greg, not sure if you will see this but in case you do, I do have a quick question. On the final table at the end, there are obviously the ratings for outside, conduit and then enclosed. I wondered, as a rule of thumb, what should we regard the van to be? We’re doing a sprinter conversion similar to yours and almost all of the cables we install will be enclosed inside the van just in plastic conduits that would run within the back of the cupboards etc, so would you consider that the insulated wall or the mounted on wall? I appreciate that you can’t take responsibility for it etc. but just wondered your opinion. Thanks very much!
Amazing articles, thanks so much Greg. I’m just working on my wiring at the moment and looking at the wiring diagrams you have provided. I’ve noticed on your writing diagrams you’ve provided, the single battery diagrams are using 4 mm² cable for the fridge but the 2 & 3 battery diagrams you use a 6mm cable . Is there a specific reason you have done it this way ? Thanks again for all the help.
Hi Greg, Thanks for such a clear, concise and informative article. I am adding a solar panel to my motorhome that is pre-wired with mains hook up and 12v circuits. Of all the articles I have seen I cannot find one that shows how to connect the ‘load’ outlet from the solar controller to the 12v distribution box. Do you simply connect wires to the terminals that the battery charger uses, or do you need to consider the wires coming from the starter battery into the distribution box? any help would be gratefully received.
easy to understand informations here. thx for that. but as far as i know the cable size is not only important to the amps you wanna put through but also the voltage will drop signifcantly if your cable are too small. that is probably not important for the usb sockets and led lights. but a fridge is maybe not switching on if you loose 10% to 20% of the voltage because your cable is too small. if the wiring is only 1 or 2 meters from the fuse box…its not too bad but if its 5 meters or more it will become a problem.
I am sure it is to far after the article to get an answer but want to make sure I got it right. The USB charger has a 2.1a (5v) and a 1a (5v) outlet which is 3.1a (5v) not 3.1a (12v). For a similar item I found on Amazon the same 2 port drew less than 2a @ 12v and used a 2a fuse. All the math in the article is right, just wondering if the math on the USB was correct?
Hi Greg Great articles, they are a massive help. However I am slightly stuck with parallel lights circuits. I have the same touch sensitive LED lights as your own build (thanks for the inspiration btw), but how do I create a parallel circuit with them because as you know they only have two small terminals? Do I need some sort of connector or am I just not seeing something obvious. Thanks in advance
Hi Greg Correct me if I’m wrong although I don’t think I am, in regards to your USB example, aren’t those outlets 5v? I guess the socket itself is a step down converter 12v-5v, if I’m correct and the conversion itself uses zero energy(I imagine there must be at least some heat energy lost), then full power would be 12.4A x 5V =62W, so the draw off the 12v system would be 62W ÷ 12V = 5.16A roughly, meaning your fuse at 15A is twice the size it should be ???
For the USB, aren’t the amp ratings of the socket at 5v, not 12V? So each socket would have a max draw of 3.1A x 5V = 15.5W? Then that’s a load of 15.5W per socket for a total load of 62W (4 x 15.5V = 62W). Then 62W / 12V = 5.16A. So a fuse rating would be 5.16A x 1.25 = 6.45A. It seems like the fuse you’ve selected is too large for the load. I’m happy to know if I’m wrong though.
Hi Greg enjoy your articles greatly. I’m just looking at getting parts for the electrical setup. I won’t be totally off grid and therefore the van will be parked up for weeks. Due to its location when parked I looking at using a 10A mains battery charger to keep the starter battery good. I’m also having a DC to DC fitted due to the van being Citroen Relay 2017 euro6 with a smart alternater . My question is.. could I Connect my battery charger to the starter battery by utilising the existing wiring from battery to DC to DC controller with the use of suitable switches therefore not running two sets of wires to the starter battery. Or can you see a major flaw in my plan. Cheers
So, a couple of constructive comments (hopefully), the lights in series wouldnt have differing brightness as the voltage would be shared between them. And secondly the fuse rating for the USB units is way out. 3A at 5V (As USB is) is only just over 1A at 12V, and using diversity they would never all be powered at the same time. So a 5A fuse is more in line with the correct requirement. Especially as you have multiple outlets on the cable.
Hi Greg I’ve been very confused about electrics, I like how you explain I just bought a van and I’m going through everything, for piece of mind. My van has got a 140 amp split relay charger. From van battery to charger is 16mm2 cable 100 amp fuse near to van battery cable runs to split charger, out of split charger no fuse to 100ah leisure battery, my question is do I use a fuse 1.25 bigger than the 140 amp charger and use larger cable than the 16mm2 that is already existing Regards and TIA Karl
Hi Greg, as everyon else says this has been a very helpful build series! I have a question regarding the best way to splice cables for the LED lighting circuit? It seems to make a three way connection it’s either spliceand solder and cover with electrical tape or maybe other dedicated connectors? Ive seen a few different suggestions about the place but can’t figure which is best. If anyone else has ideas or links it would be much appreciated
Hi Greg, thank you so much for this article and your diagrams for all of the systems you’ve put together too! I’ve found them invaluable! I’ve been trying to research the best way to splice the t-junctions in the wire system together, such as for spurring to a light fitting and I’m at a loss as to what I’m actually meant to do to make sure it works, and works safely! I’m seeing expensive solutions such as junction boxes, etc. Do I need one for every spur? What do you do or recommend? Thank you!
I’ve got the same fuse box as this and I’m wondering if anyone has had any issues with them, the thing I’ve noticed is if you pull the fuse out of the holder the warning led comes on, if you then test the positive connector beside that fuse with a multi meter it’s still showing voltage, but using a 12v screwdriver test light the bulb won’t come on. I’m thinking the fuse board it’s using a low amp current to test for a circuit but it’s also lighting one led from a multi led ceiling light with no fuse even fitted in the holder, I’ve tried removing all the fuse I’ve also got a spare fuse board of the same type that does exactly the same, which slightly unnerving!
HI Greg! Would I be safe running this solar setup? 160W panel running to a 20amp controller with 10AWG wire. Then running from controller to two 100ah leisure batteries with 14AWG wire. Distance should be around 3m. Would it be best to get the same size wire all around and just get more 10AWG, or should this be ok?
I have come back and re watched this article each time I come back to do more work on my van; I have ALWAYS hated electrics! Someone starts explaining something and my brain goes into overload EVERY single time 🙁 !!! Greg makes it so very simple, visual too (I’m a visual learner, and slow uptake) Greg takes complicated stuff at a steady pace, showing different ways. Also met this guy once in person he is simply and A1 person; too bloke, too articles, we are incredibly lucky to have you Greg! (I follow Eamon and Bec too, not many others anymore, & believe Greg’s articles have made it all the way over to them too! Eamon uses them a lot too!) all our best to you Greg
I’m a bit confused. I could follow you up to when you said the 8 x 1.8 wt lights would draw 1.2 amp and therefore you would go to a 2 amp fuse. You then said you would use 1.5 mm cable. isn’t that way over the top as table 4d1a in 18 th edition says 1.5 mm cable would allow you to draw 20 amp if clipped direct. Please let me know if I’m missing something. I was thinking of using .75 cable and even that is way over the top. .?
Just bought a Fiat Ducato L2H2 and about to start doing my first ever build. Been wandering around all over the place looking for information, tips and brains that can take the place of mine in things like Electrickery which totally eludes my grey cells. Running around in circles it started to feel like…and then I found you Greg. Yours is the clearest and most informative article I have found. Thank you SO much! I shall recommend you.
Hi Greg can you please help me ? When I’m travelling my fridge in my Adria shows it’s on 12 volt but after a few miles down the road it beeps and the 12v light on the fridge flashes and by the time we get on site it’s defrosting !! Any ideas ps great vids I’m just going to press that sub button 😎thanks Chris Isle of Wight
Great job on these articles Greg, I can really see you have the motivation of helping people and I appreciate that very much. Most of the other creators try to sell everything such as the diagrams and I really love the fact that you share them for free for all of us to learn from. Keep up the good work!!
If my fuse block is on one side of my trailer and I have 4-5 circuits crossing roof to opposite side can I send positive and negative to a distribution bus bar on other side and and branch my circuits from that source? I am using 12 wag and would likely branch with 14 wag. These are low amp led light circuits.
Thanks Greg! I am now planning my electrics. This article makes it really simply, especially working out the fuse size and cable size. I can now buy my lights and work out the ratings needed for cables. I take it with something like a 5 gang 12v switch panel it does the same job as having a fuse box with negative block, so you can then see the voltage coming from the battery?
Hi Greg, just wondering, I’m having a few problems working out the electrics for my van. Will 18 amg red/black wire, think its 0.85mm2, do the job for my 4 led spotlights at 3 watts each? So 1.25amps with the added 1.25 percentage you recommend,with a 2amp fuse in the blade fuse holder? Cheers in advance if you can help.
Hi Greg, thanks for another really informative article. this might be a silly question, but as they say the only silly question is the one not asked. I’m abit confused, when choosing the cable sizing for the lights why did you go for 1.5mm2 not 1mm2, as it seems all the figures on the table for the 1mm are significantly larger than the lights combined ampage. the only reason I ask is that I’m a complete rookie and just wanted to make sure im reading the table correctly. hope that makes sense. all the best to you and the family, Rowan,
Greg, hoping I can pick your expert brain to unscramble an electrical conundrum (should have paid attention to physics at school!). I am considering underfloor heating mat for my van and having watched your excellent article on cable and fuse sizing, the following is baffling me. The product is quoted as Heating film 1 meter long 300mm wide 67W/m. It further then states: Power 220W/m² Voltage DC12V Max temp. 55°C Thickness 0.33mm. I don’t understand the correlation between the first W/m number and the W/m2 number, finally how do I calculate the amps in order to cable and fuse size? Hope you can help!
I started using ENT flexible raceway years ago..As I can use Blue for AC wiring. Then use Orange for DC low voltage wiring. Then I pull a few pull strings in with the wiring. Just in case they want to add wiring later on. I also use the boxes designed for ENT Raceways. Then mark the cover plates with the proper breaker\\circuit numbers. I also use automotive grade wiring…. As you said an RV gets hot\\cold in them walls. So the extra cost is worth the peace of mind…. And it meets NEC, NFPA70 code….
Hi Greg, if I disconnect my Batteries from my VE MPPT CC, then the load coming from the PV will damage my MPPT, would it not? How can I protect my MPPT CC against possible battery disconnect? In your diagram, you have a circuit breaker between the MPPT and the batteries, what if the breaker trips, then the PV load will damage the MPPT?? Thanks
You’re God’s Blessing, Praise God. It’s very uplifting to know there’s still plenty of good hearted people liked you in this world. May Jesus Christ continue blessing you and yours 💘. Not that yeah, I understand everything, it’s contrary, but I’m here for your kindness. But so far, I’ve learned which cable to use and not to us !👍 🙏🙏🏽✌️☮️💟
Sorry, but at 17:29 you are very wrong. The 3,1A is at 5 volts. Given a 90% worst case inefficiency of the internal 12V to 5V Dcdc converter, each socket can draw about 17 watts, which in 12V is 1,42A. 4 of these brings the current sum total for this part of the circuit to about 5,7A, not 12,4. Big difference, and I’m a bit puzzled you do not know this. Also, how many amps you can run through a cable also depends on the length of the cable.
Hi Greg, I hope you are well. Can I please ask your advice on cable size? I have a Renogy 60A DC-DC charger, and I need to run cables from the rear of the van where the charger is to the starter battery which is in the passenger footwell, so a max of 6m. I have a bank of 4 x 100AH lithium batteries. I am thinking 35 mm square cable. Do you think that would be a safe choice? Many thanks, and love the website!
Great explanation. One thing to note, when selecting switches for circuits make sure you size the current rating of the switch to be GREATER than the fuse rating. When selecting DC switches for use in a small panel mount, circuits with loads above 5-amps, use a relay. You will not find affordable and reliable small high-current DC switches. DO NOT use AC switches in DC circuits!
Hi Greg. Great articles. My wife and I have been following you since the first lockdown when we decided to move house (down size) in order to buy a Sprinter (LWB) to convert. So.. we’ve moved. Painted decorated and repaired the house. We’ve bought the van and so far installed the windows, a Skylight, Maxxair and Maxxdome in the roof along with 525W solar on the roof and a Wi-Fi Antenna. Tomorrow I’m wax oiling the underneath….Then… I’m on to first fix wiring. Your “Electric cable and Fuse sizing” article is great and has given me the confidence to start. I am however confused as to how you (in your article) selected the 1.5mm and 2.5mm cable sizes. I have the sizing chart ….. but I must have missed a trick to understand how to use the chart. Please guide me. Ps: I retire at 66 next March so my wife and I are embarking on the “one foot in the grave” tour 😂
Hi Greg, I’m just trying to find out what size cables I need and have a question. I’m confused on the type of cables. Everyone seems to use the same amp chart as yourself, but isn’t this for standard wall cables? Why doesn’t anyone recommend thin wall automotive cable which seems to have almost double amp carrying capacity and much higher working heat range? I am a novice so please forgive me if I’m missing something.
Greg, you should have become a teacher!! I am 58, no electrical guru, but wise enough to learn from others!! I love that Watts circle!! The max amps theory, basically everything!! You teach as if I am a dummy and I love it!! All just to make sure!!! Very nice! Thumbs up, subscribed, bells on!! Great job!!!!