Electric question - Lease trailer

[mikemorvan]

I reworked and wired this trailer a few years. My primary wire is too small. When the a/c or space heater come, if other lights are on they draw down some. I want to get this corrected. What size wire do i need?

Six circuits:
1 - One light and fan
2. - One light and fan
3. - Two ceiling lights
4 - Four outlets
5 - Exterior lights. One coach light. Two double floods. Neither are on very often.
6. Space heater plug

[Chase4556]

How far is the run from the power meter or whatever you are getting power from, to the trailer?

[mikemorvan]

Larger pic of panel / box if it matters

[mikemorvan]

How far is the run from the power meter or whatever you are getting power from, to the trailer?

Probably about 90'. It's operated fine for several years, minus the draw down issue. I use big RV power cords.

[Chase4556]

Im no electrician, but I ran 240v to a shed in my back yard and it was right at a 100’ run(90 something). I used 4awg wire. I put in a sub panel with a 60 amp main breaker. Did fine with everything I ran in there which was a few lights, small air compressor, 12k BTU mini split, mini fridge, and some other small draw misc items.

[mikemorvan]

My wire is only about 7' long. It ends as a pigtail just outside the trailer.

[Chase4556]

Oh well that makes it a lot easier.

For what you are pulling and such a short run, I’d think 6awg would be plenty and overkill even, but should be a safe bet. Again… not an electrician.

Like this:

https://www.lowes.com/pd/6-3-UF-Wire-By-the-Foot/3345390

[mikemorvan]

10-4.

[doright]

What is the sullying the power?Is it a generator or shore power? I might not understand the picture correctly, but it looks like an extension cord plugged in for your supply .

[Chase4556]

I still wonder if the extension cords you are using are causing voltage drop over the 100ft run and that’s what causing the draw down you are experiencing.

[Big_gun]

i think those RV cords are usually #10, are the lights LED? ... i'd guess the AC is 15A max heater is prob little more or close, total you might have shy of 30A? that at 100' is going to need Special (what size breaker do you have at the panel feeding this), looks like you have a #10 now.

[mikemorvan]

I’ll have to check the breaker size on the power pole this weekend. I just plug the cords into an RV outlet on a power pedestal. I don’t think the lights are led, don’t remember. I can check that as well.

if needed I can get bigger wire and make my own power cord.

[KenWood]

So lets say for the heck of it you are pulling 30 amps max.

2(paths there and back)x12.9(constant for copper)x30(amps)x90'(distance) divided by 7.2 volts (3% allowable voltage drop) = 9,675 circular mills.

A #10 is 10,380 circular mills which is adequate from a voltage drop perspective.

Now we look at actual amp draw. It is either considerably more than 30 amps or you need to check your connections. Anything appearing blackened or blue is having heat building up from a loose connection. It looks like your AC is a standard 5-20P cord so there is probably no more than 16 amps(not likely). I would assume the space heater plugs into a regular outlet as well. If connections are tight and you are not plugging large load items in the other plugs then the problem could be the service drop from the power provider. This is usually the problem when lights draw down. Is this meter the only meter from the pole mounted transformer?

If you are drawing 30-40 amps it would be best to change to number 8 feed.

I'm willing to bet it is on the utility company's side.

[mikemorvan]

Nothing black or blue anywhere. I just talked to the ranch hand / electrician. He thinks there may a problem with a neutral wire in the power pedestal. He is checking that tomorrow. I'll be repulling my main supply wire with bigger wire regardless. We'll see....

BTW - pretty fancy math. I've never heard of a circular mill. Thanks for the info.