Electrical question help please!

[s/v Jedi]

I have awg8 cables going up the masthead for navlights... at 12V non-LED it's pretty normal.

[hellosailor]

Gord-
American Wire Gauge table and AWG Electrical Current Load Limits with skin depth frequencies and wire strength

Scroll down, that's the table I was working from.

[St. Elsewhere]

The table cited above for power transmission appears to be intended for a primary distribution utility system where the voltages would be 4 KV to 12 KV.

This table is more applicable to our boat circuits: http://assets.bluesea.com/files/reso...ence/21731.pdf

[DumnMad]

Originally Posted by David M

You need to do the basics. Measure the current going through the wire and then check the wire guage tables to determine if the wire is guaged correctly for the wire guage and the run. You can get an idea of the current by adding the wattage of the bulbs and then dividing by 12 volts....which will give you amps of current.

If the wire guage is inadequate an easy but expensive solution would be to replace your existing incandescent nav light bulbs with LED nav bulbs. They can't be any LED bulbs though, they have to meet the COLREG technical specifications for nav lights and the lav light manufacturers requirements.

If the wire is warm then voltage drop will mean less voltage at the bulbs and dimmer lights.

[hellosailor]

Ah, kilovolts. Ooopsie, must be a lot of folks looking for small kilovolt circuit specs to have pushed that one up so high on Google. My apologies!

[Captain Bill]

I do admit it has been a long time since I was an electronics technician, but if I remember correctly we never used standard AWG wire for kilovolt work. I did a small stint building high voltage power supplies in the early 70s and the wire on the high voltage side looked almost like a spark plug wire. I believe that AWG wire insulation is only rated for 600 volts. I seriously doubt that a chart for standard AWG wire guages is intended for KV use.

The charts that I use for my wire sizing are the ones in the west marine catalog which compare well, if not exactly with the Blueseas chart. On the other hand looking at the posted chart American Wire Gauge table and AWG Electrical Current Load Limits with skin depth frequencies and wire strength there seems to be a disconnect. If you are to take the power transmission rating one would expect that the voltage drop charts would begin at that rating rather than the chassis rating. If one uses the calculator at the bottom of the chart, one sees that the chassis rating gives a 10% voltage drop at the chassis rating and a 3% at the power transmission rating for short runs (I used 10 feet one way) at 12V. It would seem that if I use a 3% drop chart I'm getting the proper results for the power transmission rating. Indeed 8 guage is about right for an incandescent bulb up a 60 ft mast bundled with other wires.

[rwidman]

Originally Posted by Dulcesuenos

Maybe its a #10 wire then.

Just so we can get this out of the way, the wire gauge should be printed on the insulation along with some other information. Look at the wire, read the gauge, and you will know. It doesn't matter what size connector was used, someone at sometime could have used the wrong size connector.

As for the wire being warm, it should not be warm. You have a problem.

[Greggegner]

First measure the amp with the lights on and then with the bulb out and the switch still on ( that should be 0). The wattage of the bulb should decide the amps. Assuming 12 gage wire you should not feel it get warm.

[Dulcesuenos]

I found a larger wire that was feeding one end of my switches and all electronics plus the gauges. This wore had a severely damaged section almost cut thru. Not sure if this was the cause but i fixed it and it does not seem as though the wire going to the running light switch is not getting hot anymore. Seems interesting as the damaged wire wasnt getting hot

[rwidman]

Originally Posted by Dulcesuenos

I found a larger wire that was feeding one end of my switches and all electronics plus the gauges. This wore had a severely damaged section almost cut thru. Not sure if this was the cause but i fixed it and it does not seem as though the wire going to the running light switch is not getting hot anymore. Seems interesting as the damaged wire wasnt getting hot

I don't think this had anything to do with your original problem. It's good that the wire isn't getting hot any more but you really should find out why it was getting hot so you don't end up with an electrical fire some night.

Calling in a marine electrician to go over your electrical system would be the safest bet here.

[Dulcesuenos]

Originally Posted by rwidman

I don't think this had anything to do with your original problem. It's good that the wire isn't getting hot any more but you really should find out why it was getting hot so you don't end up with an electrical fire some night.

Calling in a marine electrician to go over your electrical system would be the safest bet here.

I agree, going check the bulbs replace w led, clean connections re check and go from there