Adding a 12v auxillary socket

[Dungoisdadsbongo]

Hi Guys,

Would someone please offer done guidance with regards to the above?
I'm planning on adding a twin 12v/Dual USB socket where the rear ashtray sits on the Center console. I'm planning on splicing the front 12v socket feed and piggy backing off that. The bit I'm unsure about is do I need to fuse the new socket if coming off the existing one and what amp wire is recommended?

Thanks in advance,
Gary

[mikeonb4c]

Hi Guys,

Would someone please offer done guidance with regards to the above?
I'm planning on adding a twin 12v/Dual USB socket where the rear ashtray sits on the Center console. I'm planning on splicing the front 12v socket feed and piggy backing off that. The bit I'm unsure about is do I need to fuse the new socket if coming off the existing one and what amp wire is recommended?

Thanks in advance,
Gary

Better maybe to run a suitably rated and fused new feed direct from the battery, preferably leisure battery if one fitted? The standard one will be fused but may not sufficiently to cover all you might get up to with three sockets (although maybe you'd be ok with just usb use). But in any case, when i did this i preferred not to interfere with standard wiring where avoidable - but maybe thats just me!

[Dungoisdadsbongo]

Better i think to run a suitably rated and fused new feed direct from the battery, preferably leisure battery if one fitted. The standard one will be fused but may not sufficiently to cover all you might get up to with three sockets (although maybe you'd be ok with just usb use).

Good advice Mike, thanks. Most coming of the 3 sockets at once would be a DVDs player and a couple of phones/tablets. If that's to heavy for an existing fuse then I would have to wire straight to the leisure battery, if the it's the latter then could you recommend a suitable fuse and wire amp?

Thanks

[g8dhe]

Each socket is rated at 10 Amps, you choose the wiring to handle both the Max. current demand and also to avoid to much voltage drop if its a long run, once the cable size is known then you fuse to protect the cable itself. Whilst you might expect only low current demands now, in the future chances are you will plug in something larger like a tyre pump which will demand the whole 10 Amps! I would go for 25 Amp cable 2mmSq and a 20 Amp fuse rating direct from the LB. See http://www.vehicle-wiring-products.eu/p ... sq-28-0-30 or similar.

[Dungoisdadsbongo]

Fantastic,
Thanks again Geof!

[Dungoisdadsbongo]

Following on from this recent advice, I've tried to install it today and failed
This is what I have done:
I have train core 21 amp 1.5mm2 cable which connects to on of the 12v sockets and I have spurred off the first socket onto the second. The cable then runs about 2/3 meters and I have joined the live feed to another cable which includes a 20amp small blade fuse (this cable is larger and I assume 25amp)
https://rover.ebay.com/rover/0/0/0?mpre ... 2350767941

Then the fused live (larger cable) goes directly to the positive terminal and the 21 amp earth feed goes to the negative terminal - both on the leisure battery.
I am connecting the live first and then the negative and this is blowing the fuse every time. Is it because of the two differently rated cables or something else?
Please help
Gary

[g8dhe]

I really can't make out what you have done from the text above, I don't want to make assumptions as that leads to errors.

Why have you spurred off the existing wiring (not sure you really mean spur perhaps?) ? The existing wiring is not rated for additional current .....

The added fuse MUST be close to the leisure battery, its purpose is to protect the cable leading away from the battery so it needs to be within a few inches of the battery, nothing else, if you put the fuse several metres down the line then that fuse is doing nothing to protect the cable between it and the battery. The cable and fuse I suggested is for feeding the NEW ADDITIONAL sockets ONLY, not for connecting to existing sockets.

[Dungoisdadsbongo]

Sorry Geoff it's not clear.
The new 12v auxillary is a twin socket so the spur is allowing connection of both from the 21 amp cable which leads to the battery. The fuse and larger cable (joined to the 21 amp live) are about 6 inches from the battery.

[Dungoisdadsbongo]

I guess I'm stil not being very clear, apologies for this let me try and start from the beginning;

I have connected an in line mini blade fuse (20 amp) and holder which I purchased from eBay, which is in the link above to the positive terminal on the leisure battery. Looking at the size of the cable on this it is more likely to be rated at 30a. This is about 6 inches from the battery.
I have then joined/soldered to this a cable that is 21 amp which then runs around 3 meters to the positive connection on a new 12v auxillary socket. I have also used the another length of the 21 amp cable to connect to the negative terminal on the leisure battery and this also runs 3 meters and is connected to the negative on the new 12v auxillary socket.
I have then come of the positive and negative connections from the first auxiliary socket using the same 21 amp wire and connected to the 2nd new 12v auxillary socket.
As soon as I reattach the negative terminal on the leisure battery the fuse blows.

I'm wondering what would cause the fuse the blow?
Differently rated cables on the same circuit?
Poor solder joint between the 30a and 21a cables?
I'm completing the circuit without yet plugging in the new 12v sockets onto their relevant connections?

I'm really at the start of understanding basic dc electrics so any advice would be appreciated.

Regards
Gary

[Bob]

I can only think there is a short inside one of the new sockets, diffreent size wires and soldered joints can't cause the fuse to blow, but without looking it's very difficult.

You would also be better running the earth wires to a sound earthing point near where the sockets are fitted, rather than running a wire back the the LB. There is a sound reason for this which will take a little while to explain, but it will not be causing the fuse to blow.

However, Geoff is out top electrical chap.

[g8dhe]

Yes, the wires themselves aren't your problem. It sounds like you have a short between +ve and -ve and the first place to look is the sockets themselves, the cheap varieties from Ebay and the like are frequently the cause of these problems with missing insulation disks. If you can put up some pictures it would help a lot identifying likely problem areas.

[WestyK]

Hi.

I think you need to start tracing things back or eliminating things.
It sounds like you have a short between pos and neg somewhere.
The most likely is one of the sockets I think.

Do you have a multimeter? this could make things easier.

Here is how I would start.
1. Double check none of your joints are shorting out with each other.
2. Check that the positive isn't touching the the body of the van anywhere (dont think it will be this is you say it only blow when you connect the negative).
3. Disconnect each socket one at a time then connect the cable to the battery making sure that there or no bear cables touching anything or each other.
4. If your still blowing fuses with both cables disconnected from the sockets and not touching anything or each other you have then narrowed it down to a problem with the cable somewhere.

If you have a multimeter you could check continuity of the pos and neg terminals of the sockets when disconnected. they should be completely open circuit.

Good luck.
Ian

[Dungoisdadsbongo]

Thanks for sticking with this guys, it's appreciated. It has been short circuiting before attaching to the sockets. Thanks to everyone's input I've traced the cause back to me being haphazard with the cables before actually connecting them to the new sockets.
A case of not seeing the wood for trees.

It works now!

Best
Gary

[Bob]

Well done.