6 replies to this topic

[si-supercharger]

Hi in after some feedback from
Other peoples experience, as it might save me allot of fault finding .

Issue 1) I'm in the process of wiring up a facet fuel pump, but the Earth to the illuminated switch melts instantly and I think I noticed the lights on although not switched on when I went to disconnect the battery to prevent fire. It's wired with a new suitable wire direct from the battery to a fuse box with a 10amp fuse then to an inertia switch, then to a relay. To energise the relay I have taken an ignition live from the factory fuse box, but before connecting to the relay it's been wired via a new illuminated switch, which has its own earth for the illumination. As soon as its switched on it powers the pump but burns the earth to the switch out ? The other telay points are obviously earth (no issues) and power from relay to fuel pump. All wiring inc main. Look is brand new. Does this sound like a short circuit or have I put the switch in at the wrong point I.e should it be between the relay and fuel pump.

Issue 2) I need to have some extra take offs for switched live to energise about 5 relays. Obviously I can use the spare take offs from the standard fuse box, but I think this would overload it and cause heat/fire issues. How/where can I create more safely ?

Any help would be appreciated.

[sledgehammer]

 I need to have some extra take offs for switched live to energise about 5 relays. Obviously I can use the spare take offs from the standard fuse box, but I think this would overload it and cause heat/fire issues. How/where can I create more safely ?

Any help would be appreciated.

 

Someone on here sells  a fuse box loom that is independantly wired thru a relay to the solinoid terminal

 

the relay is triggered by the ignition switch

 

just copy that - or buy one

 

can't remember their name

[matt050990]

Wilson 1330. Or wired by wilson is your man!

[sledgehammer]

thanks Matt - found it ...

 

http://www.theminifo...s-l45-plus-p-p/

[matt050990]

Can't ask for a better bloke for wiring. Top quality goods all the time!

[si-supercharger]

Hi thanks all for the help with the extra switched live query. Looks simple enough, basically battery/starter take off wired to a new fuse box via a relay with the relay activated from an existing switched live from the factory fuse box then piggy back the feed along the new fuse box for more fused connection take offs right ? It's going to make things complicated though, as the way I see it is this is basically a relay fed fuse box feeding the switched live for other relays via its fused take off/connection points, and then the things that the relays are powering are fused again. I.e double relays and double fusing !!! I have no issues with identifying the correct rated fuses for the items being powered via the relays, but what rating fuse/s and wiring type from the new fuse box to the relays should be used. I assume the power requirements for relay switching are minimal, therefore fuses need to be low rated? But with everything electrical assumptions don't cut the mustard, so specifics from those who know more than me are really appreciated

[Cerberus]

I've just rewired a TVR Taimar that my Dad and I are rebuilding, this was a complete rewire from scratch.

I've used ignition relays as mentioned above, to reduce load on the ignition switch, and to modernise the system.

 

I've used 16.5A thinwall wire almost everywhere, apart from where there is a higher current draw like the heated rear screen etc.  So to sort out what wire gauge you need, you'll have to list out what you want to relay, and calculate the load that will/could be drawn and go from there.

Amps = Watts / Volts

 

Fuses obviously then need to be a lower rating than the wire, but not lower than the draw of the item.  Remember that glass fuses rating is the max the fuse will blow at, whereas blade fuse ratings are the continuous current rating.  So basically, a 35A glass fuse will blow when 35A passes through it, but a blade fuse of the same rating won't blow straight away at 35A.

 

 

It's also got an electric fuel pump, and like you, I've relay'd it, but it's connected to the alternator signal wire so that the fuel pump only runs when the alternator is charging, so engine stops, fuel pump stops.  I've also fitted a momentary switch to prime the pump, this is just connected up to the low side of the relay with the alternator feed wire.

 

 

With regards to your burning wire, check that the connections on the switch are all correct.  Apart from that I can't really see why it should burn out the earth wire for the light, as no major current should be going through there, just the few milliamps for the LED, if it's burnt out the wire, then the LED in the switch is probably dead now too, so might be easiest to just get a new switch to rule out that being duff.