All prices are in Australian Dollar (AUD)
The first thing I will mention is that installing “Low Voltage” (240V) cabling in Australia is illegal without an electrical license. This blog post and video episode is only for sharing ideas and concepts. This post will focus on the installation and plan of installing the cabling (rough in) for the electrical in the van.
As mentioned in other episodes, this van is designed to be completely off the grid in terms of energy needs. However it will also be able to plug into mains power when desired as well. There are 3 different ways that the battery can be charged in this particular setup.
Number one and will be the most common is from the 580W solar system. Number two which will also be extremely common as well is charging from the alternator whilst driving, which will kick in and activate automatically via a relay in the charge unit. Finally three is plugging into a 240V mains outlet via a 15A extension lead which I’m hoping I never really need to use unless for a special circumstances.
I wanted to have as many things as possible running on 12V DC as this is what the battery voltage operates at. This allows me to tap straight into the 12V without needing to invert or modify the voltage or waveform just to run for example a light. So my fridge, cooktop ignitor, HWS, water pump, toilet, maxx fans, lights and various socket outlets are all running on 12V DC.
However I will need access to 240V AC to runs loads like a Nutri-Bullet (blender), toaster, laptop charger, camera chargers etc which means I will need to install AC cabling and use an inverter. I allowed for four 240V powerpoint outlets, one above kitchen bench, one in the safe, one next to the bedside and one external outlet.
Between the mix of the 12V and 240V outlets, should both suffice with all the energy requirements I need to be comfortable and have easy access to electricity anywhere in the van.
The electrical wiring rules that outline the minimum requirements for most electrical installations in Australia are governed by the legislation AS/NZS 3000, which is basically an electricians rule book.
Furthering this AS/NZS 3001 “Transportable structures and vehicles” (a seperate rule book) are additional laws on top of AS/NZS 3000 that are to be complied with when installing electrical in a vehicle.
The electrical laws in your country are almost certainly different to Australia/New Zealand and you will have to consult your local electrician for advise.
Not all products could be found online to link to.
To be honest I didn’t draw out a plan or schematic diagram before or whilst wiring the van. I worked it out roughly in my head and just went from there until I was satisfied and believed i’d wired everything.
I’ve drawn a schematic and labelled some photos after the fact so it is easier to explain exactly what I have done.
12V DC Wiring Diagram
240V AC Wiring Diagram
The fit off and wiring will be explained much more thoroughly and in depth in Electrical Pt. 2, however I will mention some things here. This should make sense to an electrician, but if it doesn’t to you that’s okay.
The inverter has an Automatic AC Transfer Switch, and detects mains input voltage. This means when mains voltage is detected the inverter flicks to “Mains Mode”, which diverts all the AC loads to operate directly from the mains AC input.
When mains voltage is disconnected, it automatically switches to “Inverter Mode”, diverting all AC loads to operate from the inverter, essentially powering the AC loads through the inverter from the house battery.
The inverter is equipped with something called a Neutral to Ground Relay. This is designed to automatically connect the inverter output neutral to Earth when the AC transfer switch is open (off grid), which is called a Multiple Earth Neutral (MEN) connection in Australia.
Basically when the van is plugged into mains it is making an MEN connection through the external switchboard, so the Neutral to Ground Relay is open. When the van is off the grid the Neutral to Ground Relay closes and makes the MEN connection.
When off grid the van is actually not connected to true earth, as it is insulated from the ground/earth from the rubber tyres. However, the Neutral to Ground Relay still allows the RCD circuit breakers to operate under earth fault conditions.
As I understand it, the van chassis is where the fault current flows momentarilly to allow the RCD to trip, but no dangerous voltages/currents are present to cause harm as the trip time is extremely quick, which is the whole purpose of a Residual Current Device (RCD).
Also when off the grid, as mentioned the van is never connected to true earth. So I would think that the Neutral to Ground Relay is actually making a “Virtual MEN Connection”.
The photo below contains information about the combi inverter, particularly the 2 paragraphs in the bottom left. Click photo to enlarge.
I used a few different types of cables to wire this van, which each have a different purpose. As mentioned in Ep. 8 Solar Install, I explained the concept of voltage drop and amperage draw which plays a roll in selecting cable size.
4mm Twin – I used this cable for all my general 12V DC wiring.
2.5mm Twin & Earth – This cable was purely used for my 240V AC wiring.
6mm Twin – I used this cable from the solar isolator to the solar charge controllers. I also used it from the DC fuse on the battery board to feed my DC switch board which supplies all general 12V appliances.
6mm Earth – This was purely from where the cable is lugged and bolted to the van chassis, and up to the AC switch board.
25mm XLPE Flex – I used this to run from the van starter battery to the house battery DC2DC charge controller, so I can charge the house battery whilst driving.
Cat 6 Data Cable – I used this cable to connect the future reverse camera up to the future updated head unit.
I enclosed all 240V AC cabling in either 20mm, 25mm or 32mm corrogated conduit (corro) along its entire run. I also used a metal holesaw to cut holes through the metal studs so the corro was nice and secure.
I also enclosed a fair bit of 12V DC cabling in corro, but it is not as crucial and I mainly focused on the parts that were passing through the metal studs to protect it from cable damage.
Not every cable I ran is shown in this blog post, however all will be on the schematic diagram.
1. The first thing I did was use my 25mm & 32mm metal holesaw to drill a series of holes in the side of the van that lead into the back vertical cavity.
I ended up drilling more holes than what’s in the picture, and I also used tin snips on the metal to be able to get the drill in easier.
2. Next I measured and cut two runs of 2.5mm Twin & Earth (T&E) cable for the 10A external GPO and 15A inlet. These run back to the AC switchboard location.
I also measured off the 6mm main earth wire and ran these 3 cables all in the same 25mm conduit, as they’re going to basically the same place.
3. A good tip to get cable (especially multiple cables) through conduit or corro easier is to use a tongue (which is from tongue and groove flooring) to act as a “snake” through the corro.
You drill a hole in the end of the tongue, then cut the active and neutral conductors off the end of your cable, and strip the earth so bare copper is remaining. You then twist the copper to the tongue and tape it so it’s a smooth, strong inline join.
Always feed your cable through straight and don’t twist the wires, otherwise it’s a nightmare to get through. Make sure the corro is pulled tight so it is straight to allow the cables to go through much easier. I did it by myself which was a challenge, but two people is much easier.
4. Next i measured and cut two 2.5mm T&E cables that go from the AC switch board to the inverter. I used the tongue to get down the cavity in the wall and pulled both corro’s down the wall into position.
I also drilled some holes through the metal studs to run each corro to the AC switch board.
5. Next I enclosed the solar cables in corro and snaked them over to where the solar isolator will be going with the tongue.
6. I then re-routed all the existing 12V van wiring, which was for the lights, remote locking and roof revision camera.
7. I then drilled a hole though the timber bottom plate in the bathroom wall, and in the chassis to run the two tank gauge cables and 12V pump 4mm twin cable.
8. I doubled the end of the tank gauge cable onto itself and pushed this in the end of the corro. This is so that if I ever need to drop the tank, I will have enough slack on the cable to do this.
This is all enclosed in 25mm corro and secured with 25mm metal saddles.
9. I ran the 4mm twin down the corro and terminated this to the 12V pump wires and enclosed them in BP connectors.
10. I ran the hot water system temperature control up with the two tank gauge cables into the same location. They weren’t long enough to reach back to the switchboard area so the controls will be inside the cupboard.
I coiled all the cables up and sat them in the wall until it is sheeted.
11. I measured off the pump cable to the DC switch board and cut the cable, then ran the HWS/Toilet circuit back to the board at the same time.
The HWS/Toilet cable was still on the drum at this point.
12. Once these were back to to the board I measured and cut the HWS/Toilet cable at the HWS. I then ran a new 4mm twin to the toilet and fitted the toilet off.
Once this was done I essentially had a loop of two 4mm twin cables at the HWS, which I twisted together with the HWS wires, essentially making the HWS and toilet in parallel to each other on the same circuit.
13. Next it was time to install the 15A inlet and 10A external outlet on the side of the van. I measured them up using the waterproof seal as a template, to see how they would fit on the internal side of the van.
14. I drilled a reference hole through the center of the mark out, and remarked the templates on the other side. I cut them out with a jig saw, then filed and painted the raw edges with rust protector paint.
15. I stuck the waterproof back to the the van first, then cut the cable and corro to length, I left enough to allow some slack inside the wall if ever I need to replace the fittings.
I slid 20mm corro on each of the cables, and I zip tied at the end of the corro on the cable to keep the corro secure and from slipping.
16. Next I stripped the cable and terminated into the dedicated cable terminations. I wanted minimal white cable sheath protruding from the fitting as possible, and no single insulated conductors protruding.
After terminating I secured the anchor clamp to the cable which takes the vibration and movements of the cable off the terminations to prevent loosening terminations.
Then I clipped on the rear plastic shroud, and mounted each fitting with screws.
17. Next I stripped and lugged the 6mm earth cable. I grinded off some of the van on the paint to leave exposed metal, and bolted the lug to the van chassis with a nylock nut. I will be spraying zinc protecting paint over the lug and van metal to prevent rust.
I enclosed the earth cable in 20mm corro and secured the end with sikaflex, and put a “DO NOT REMOVE” earth tag on it. This earth connetion will be completely accessible and visible, as I’ll be cutting a 70mm or 90mm holesaw in the rear of the cupboard.
18. Next I ran two Cat 6 data cables to the rear door which will be for a future reverse camera.
Note: The van already has a reverse camera on the roof connected to a display screen in the cab, but it is more like a revision mirror as it is on all the time, and doesn’t show the back bumper.
I want a 2nd camera lower on the door purely for reversing so I can back up to objects extremely close with confidence.
19. I then ran the 25mm XLPE flex cables, I bought a 26 meter cut from the wholesaler and cut it in half two make two 13m lengths for positive and negative.
20. I ran a 4mm cable from the DC switch board to the kitchen for an above bench 12V outlet.
21. I ran the back door lights switch wire from the main switch location. I had to fit two 4mm twins + two cat 6 cables + existing 12V van wiring through the rubber corro from the van to the door.
I couldn’t fit a 3rd 4mm twin through to loop from one door light to the other, so I had to do a solder join in the wall to parallel the 2nd back door light to.
22. I then ran the switch wires from the main switch position to each of the 3 main van lights. These are all just looped to each other because they’re all on the same switch.
I drilled a 20mm hole through the van metal to fit a small cut of 20mm corro through, to protect the cable from damage.
23. I finished running 4mm twin to the maxx fans, shower light + fan, 1 x entry light, and cupboard lights. I brought the main switch cables through the van batten in 32mm corro.
24. I ran a 2.5mm T&E cable to the kitchen for an above bench powerpoint.
25. Next I ran two 6mm twin cables from the solar isolator to the battery management area. I also ran another 6mm twin from the DC switch board to the battery management area, this is the feed to the DC board.
26. I ran the Cat 6 cables to the front of the van, and coiled them up in the fuse box until I fit them off to the future head unit.
27. I sikaflexed all the parts where the corro passed through van metal to stop wear from vibration and friction.
28. I finished running the two 25mm XLPE cables through the timber bottom plate and to the car battery.
All wired and ready to sheet!
Some of these prices are discounted either from bulk buy or trade price. All prices are in AUD$
|Electrical Part 1|
|6mm Earth Cable (11 Meters)||1||12.5||12.5|
|Main Earth Tag||1||1.5||1.5|
|Earth Rod Clip||1||1.85||1.85|
|25mm XLPE Flex Cable (26 metres)||26||7.7||200.2|
|4mm Twin (100m drum)||1||1||150|
|2.5mm Twin & Earth (100m drum)||1||1||96|
|15A Clipsal Inlet||1||37||37|
|10A external socket outlet||1||37||37|
|20mm corro roll (20 meters)||1||1||21|
|25mm corro roll (20 meters)||1||1||26|
|32mm corro roll (10 meters)||1||1||30|