50 amp services at my house, need some help..
To all, We are getting ready to pour concert next to the garage for our 5th. I want to have a 50Amp box there to service it....The power box is on the other side of the house, I will be running 85 o...
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A voltage drop check on different gauges should be done (max. 3 percent in a branch circuit by code) but what is the voltage like at the panel in the house? Can be less than 120 in some cases. It's unlikely you'll be drawing anywhere near full 50 amps when at home. If it were a single pedestal in a CG min. NEC demand would be is 9600 watts which equates to a 50 amp recept. Not sure what NEC requires specifically for a single RV outlet in a house but could be as much as 80 percent of the circuit/receptacle rating.
Do you have a 100 or 200 amp panel in the house and what does a load calculation show for spare capacity? Is the 85' horizontal straight line or does it include vertical sections and horizontal changes in direction? Runs often are longer than expected. There will also be some voltage drop in the shore power cord and in a branch circuit inside the FW - it all adds up. Most things will run fine with less than ideal voltage but AC units can be damaged. I'd install a permanent voltmeter inside the FW.
Without knowing all of the details, I would go with #4 wire (plus ground) unless a calc. shows smaller is okay. You could always install smaller wire for a 30 amp circuit (or even larger for 50 amp outlet) and use a 30 amp breaker (2-pole) in the house panel if you wanted to limit demand and also save $$. If you haven't thought of it already, use a weatherproof RV style box with a 50 amp recept. and breaker in it so that you can shut the power off before plugging in.
Really tho., if you want to sub-feed the garage down the road, it's getting complex enough that you should get an electrician to look at the overall plan to make sure it's all okey-dokey and you don't make an expensive mistake.
Do you have a 100 or 200 amp panel in the house and what does a load calculation show for spare capacity? Is the 85' horizontal straight line or does it include vertical sections and horizontal changes in direction? Runs often are longer than expected. There will also be some voltage drop in the shore power cord and in a branch circuit inside the FW - it all adds up. Most things will run fine with less than ideal voltage but AC units can be damaged. I'd install a permanent voltmeter inside the FW.
Without knowing all of the details, I would go with #4 wire (plus ground) unless a calc. shows smaller is okay. You could always install smaller wire for a 30 amp circuit (or even larger for 50 amp outlet) and use a 30 amp breaker (2-pole) in the house panel if you wanted to limit demand and also save $$. If you haven't thought of it already, use a weatherproof RV style box with a 50 amp recept. and breaker in it so that you can shut the power off before plugging in.
Jim102 wrote:Depends. What do you want to run in the shop? What would a load calc. on your existing house panel show with RV outlet plus shop equip.? Even if you only want a couple of 15 amp circuits, voltage drop *could* be a serious issue for the shop plus what it would do to voltage inside the FW. You can't just tap off a circuit for the shop from the RV outlet feeder wire/cable. If you can, run the new circuit to the RV outlet via a new small sub-panel on the inside wall as close as possible to the RV outlet. If you do that and use #4 wire to the sub-panel you should be fine.
Can I run 12/3 off one of the legs to a shop in the backyard?
Really tho., if you want to sub-feed the garage down the road, it's getting complex enough that you should get an electrician to look at the overall plan to make sure it's all okey-dokey and you don't make an expensive mistake.
