30 Amp Outlet for the project

[VeggieBullet]

Hi Guys
We currently have the project plugged into a 20Amp wall outlet.
the outlet is about 60 to 70 Ft from the trailer.
So for the refrigerator and radio is fine but for obvious reasons when it gets hot the AC does not like it at all.
So we are in the mission to add a new braker to the main box so here is the main question:
What size of wire do we need to run from the main panel out to the outlet (aprox 100ft) that will handle a full 30 amp load without dropping the voltage?
Thanks

[dznf0g]

Hmmm, I'm handy, but this is where I pick up the phone and call in a favor from an electrician expert. 100' is a long run.

[masseyfarm]

Free advice on electricity is not always cheap.
But this site has some good info.
RV Electric

Chart at bottom of 30A page will give you some ideas.
Dave

Originally Posted by VeggieBullet

Hi Guys
We currently have the project plugged into a 20Amp wall outlet.
the outlet is about 60 to 70 Ft from the trailer.
So for the refrigerator and radio is fine but for obvious reasons when it gets hot the AC does not like it at all.
So we are in the mission to add a new braker to the main box so here is the main question:
What size of wire do we need to run from the main panel out to the outlet (aprox 100ft) that will handle a full 30 amp load without dropping the voltage?
Thanks

[barts]

Sounds like you have 100 feet from the panel to the outlet, and 70 feet from the outlet to the trailer. Use one of the voltage drop calculators on the net, but I think you'll find you need #6 wire to go 170 feet with less than 4% voltage drop; #4 if you want to stick to 3%.

- Bart

[VeggieBullet]

Hello guys and thanks for the fast response.
Actually if we place the 30amp Outlet it will be right next to the trailer and that will be about 100Ft from the main panel.

[barts]

Originally Posted by VeggieBullet

Hello guys and thanks for the fast response.
Actually if we place the 30amp Outlet it will be right next to the trailer and that will be about 100Ft from the main panel.

So #6 (2.5% drop) is preferred, but #8 (3.9% drop) will work.

- Bart

[Silver Goose]

Per the calculator for 120VAC, 100' of 10 AWG copper will drop about 6.2V. 8 AWG will drop about 3.9V. 6 AWG will drop about 2.4V. In my neighborhood, the no load 120V becomes 110V when everyone's A/C is running in July. If I want to maintain a minimum of 105V at the trailer's breaker box I would consider 8 AWG the minimum and would prefer running 6 AWG. Drawing 30A would probably be your worst case load (A/C + converter + fridge + microwave). The A/C by itself typically draws 12-15A depending on model. At a 30A load your 20' 10 AWG shore power cord will drop another 1.2V.

[VeggieBullet]

Well we don't really want to be run the AC/Water heater/ Microwave all at once
But it should be nice to be able to run the ac/refrigerator and a dehumidifier :-)

[vswingfield]

Originally Posted by VeggieBullet

Well we don't really want to be run the AC/Water heater/ Microwave all at once
But it should be nice to be able to run the ac/refrigerator and a dehumidifier :-)

Then you really ought to do the 30 amp setup, and do it properly.

You'll be glad you did.

[Silver Goose]

Originally Posted by VeggieBullet

Well we don't really want to be run the AC/Water heater/ Microwave all at once ...

When the A/C in our house went toes up in the middle of the summer and the all the contractors were working 20 hour days to keep up, it sure was convenient to have a "spare house" in the backyard. I was really glad the wiring was adequate for the needs.

[barts]

Originally Posted by Silver Goose

When the A/C in our house went toes up in the middle of the summer and the all the contractors were working 20 hour days to keep up, it sure was convenient to have a "spare house" in the backyard. I was really glad the wiring was adequate for the needs.

The Tin Pickle sits in our driveway - it's the earthquake preparedness shelter.

- Bart

[Jammer]

Originally Posted by VeggieBullet

What size of wire do we need to run from the main panel out to the outlet (aprox 100ft) that will handle a full 30 amp load without dropping the voltage?
Thanks

There will always be some voltage drop so it's a tradeoff between how much voltage drop you are willing to tolerate and how much money you're willing to spend.

Plenty of calculators like this one to use: Voltage Drop Calculator

You'll lose a 1-2 volts in your shore power cord too.

There are a couple of approaches to consider. You could run #10 copper which would give you a 7 volt drop at 24 amps including the shore power cord (we would size for the typical load not the exceptional situation where 30 amps are required). That's not great but it's better than many campsites and may be good enough.

As others have suggested you could run heavier cable, #8 or even #6, but that becomes expensive quickly.

Or you could run 2-4-2 aluminum triplex which would be cheaper and keep the drop down to 3 volts, 1.3 in the cable run and 1.5 in the shore power cord.

The aluminum cable is much cheaper in large sizes than copper and is widely used for underground runs.

[perryg114]

I ran some aluminum wire out to my shop. It was aluminum house trailer hookup 3 wire with ground direct burial cable. At the time it was cheap at around $1 per foot. I expect it is a little more. I put in a sub panel in my shop. This wire was good for 100A. You need to make sure you have aluminum compatible connections on both ends and there is some grease you apply at both ends to reduce corrosion and arching. I expect #8 copper will get you there if you go that route. You won't like the price tag on that stuff.

Perry

[clancy_boy]

Keep it simple, do this project with COPPER wire and copper designated breaker and outlet. Put the wire in conduit buried to the required local code for depth in ground - here it's 24 inches. I don't care if it's direct burial cable - that's not the only reason you put it in cheap conduit. Install your outlet box - run the wire (in conduit) and pull it to your main panel where you will install the 30amp 120v breaker. At this stage if you feel uncomfortable about working in a hot box (for good reason - it can kill you) hire an electrician to make the final connection to power. By now you have saved well over half and maybe alot more of the cost of installing this by doing it yourself. Why scrimp on cost of quality material when you are saving 50% or more already. Total cost should be well under $300 for box, conduit and fittings, glue, breaker, and wire (100 feet is a long run and that is your major cost in materials). You will be the happier for the power to do whatever you trailer was designed to do.