Fuses?!?!?

[n.gardner]

So i have four NAVIGATOR off road lights on a bar on my roof.
Every time i flip them on it blows a fuse and sometimes destroies the casing.
i've tried 20 and 30 amp fuses ?
What do i do?
thanks

 

[FIND]

Check for shorts. If you are using 30 amp fuses, I hope you are running pretty heavy gauge wires. If not, you may have just burnt through the wiring and created a short. You may be better off to run pairs on separate switches/wires/fuses.

 

[OneLever]

Please do not continue using the wiring setup you have. You need to fix it ASAP before you burn down your truck or melt the existing harness. See this thread: Link

 

[BrianDye]

I would second that you have a short somewhere in the wiring. I would only wire a pair to a switch, not 4 on one switch. Also use heavy gauge wiring, 12AWG minimum id say.

 

[n.gardner]

yeah....well dumbass myself wired them all four to one switch, even thought the box came with tho switches.
Prob oughta put the second switch to good use.

 

[rookieshooter]

The instructions that came with the lights, does it mention relays?
I have for each pair of lights, one switch and one relay on my truck.

If it does, there are threads on how to wire up these relays and switches.
Regardless I would incoporate relays.

 

[Bill Kemp]

If you are using a relay you can use one switch.

How did you wire upthe lights?

 

[FIND]

Here is a pretty basic chart that works for short runs of wiring.

These are bare minimums, therefore, for anything you are using a 30 amp fuse on, it needs to be greater than 10 gauge wire. Fuses are there to protect the wires. Therefore you always fuse something at a lower amperage than the maximum current the wiring can support.

If I remember what comes in those navigator light kits.... it is all 14 or 16 gauge wire.

You can run them all off one switch if you use a relay, but the power wire for the relay better be 8 gauge, and you need to split the power wires to each light individually after the relay.

 

[Tmac11]

Find out the amp rating of the light(s). Without this you are shooting in the dark. After you know this utilize the chart above. Also as mentioned above google those lights and see how they should be wired(series/parallel) and with what(relay?). You will probably want to check ALL the connections with a multimeter to see what has high resistance.

 

[FIND]

Find out the amp rating of the light(s). Without this you are shooting in the dark. After you know this utilize the chart above. Also as mentioned above google those lights and see how they should be wired(series/parallel) and with what(relay?). You will probably want to check ALL the connections with a multimeter to see what has high resistance.

The lights will be fine. Even if you were using 100 watt bulbs on a 12 volt system, you wouldn't exceed 8.3 amps. Fuses are designed to protect the wiring, not the appliance. 4 55 watt lights wired in parallel though is almost 20 amps, so there is no way the wiring could have survived that draw. Like I said before, run heavier wire or separate it into smaller circuits.

 

[Tmac11]

All true. Fuses are made to be the weakest link and blow to protect the circuit. But I have seen a few crap crimp connectors when subjected to more amps than they are rated for that get slightly burned up and like to cause grief. Just trying to save him some grief of taking it all apart again.

 

[FIND]

resistance from connectors should not be a problem either.

 

[Tmac11]

I am not trying to second guess anything you say but I have seen more than my share of connectors go bad from a "higher than rated" amp draw. The fuel pump connectors on my CTS-V with a boost-a-pump is a prime example. I was trying to save him some trouble by checking everything and being done with it.

 

[OneLever]

it blows a fuse and sometimes destroies the casing.

If he was running enough current through those wires to melt the switch casing then he probably fried them. n.gardner I would replace the wires you were using with new ones of the correct size. Tmac11 you are correct that a poor crimp connection will cause resistance and possibly issues. Any incomplete connection forces the current through a smaller surface area of wire thus raising resistance. FIND that ampacity chart appears to be quite conservative, which in this case is not a bad thing, just stating.

 

[98 5oh XLT]

Trust me when I say this....use proper gauge wires....use relays....and if needbe deal with extra switches. The grief caused when you have a wire go melty is NOT worth the shortcut you took.

 

[FIND]

If he was running enough current through those wires to melt the switch casing then he probably fried them. n.gardner I would replace the wires you were using with new ones of the correct size. Tmac11 you are correct that a poor crimp connection will cause resistance and possibly issues. Any incomplete connection forces the current through a smaller surface area of wire thus raising resistance. FIND that ampacity chart appears to be quite conservative, which in this case is not a bad thing, just stating.

That is a slightly conservative measure over a 5 or 10' run on average copper strand wire (can't remember and don't feel like calculating it, this is good enough for ANYTHING you need to do to keep from making fire), sure, a wire can carry MORE current than that, but it will be getting pretty hot then. I wouldn't even bother to calculate anything less than that, especially when you consider how corrosion and splices can increase resistance, thereby decreasing the current a wire can carry. Anything longer than 15' I would get even more conservative than that. I can look around, somewhere I have a good chart that gives much more complete figures... I know one of my parts dealers gave me a really nice chart back in the day when I still worked on trucks (for trailer wiring).

 

[OneLever]

I tried to get a hold of the NEC tables but they require a subscription. The NEC 2011 ampacity table in a home wiring book I just picked up was not as conservative. While you can never go wrong with safer gauges the cost per foot does add up.

On a separate note, what is the highest temperature easily available split loom you've seen around? The starter motor cables are protected in some as they run under the engine, but I don't know the ambient temperature they need to withstand.

 

[FIND]

I tried to get a hold of the NEC tables but they require a subscription. The NEC 2011 ampacity table in a home wiring book I just picked up was not as conservative. While you can never go wrong with safer gauges the cost per foot does add up.

On a separate note, what is the highest temperature easily available split loom you've seen around? The starter motor cables are protected in some as they run under the engine, but I don't know the ambient temperature they need to withstand.

Starter cables don't need heat shielding, there is air movement, and they aren't in direct contact with anything REALLY hot. The loom is just to protect them from the elements..... I know at napa you can get the woven loom, and that stuff holds up to heat pretty well, but split loom.... well, it is plastic, so you are never going to get a split loom that holds up to high heat. If you were really concerned with heat, I'd wrap them or put them in one of those woven looms.

 

[Tmac11]

Cableorganizer has some flexible nylon ones rated at 125C. If you need something higher than that DEI makes heat sheats in multiple diameters and up to 50' in length. On my other vehicle my alternator wires are an inch or less away from my headers and the sheaths have worked great.
To find out what you need get a temperature sticker or crayon style pen tester ands see how hot that area gets.

 

[OneLever]

Thank you for the tips FIND and Tmac11. The stock wires appear to have only normal plastic split loom around them but I intend to beef them up when I rewire them later.