Electrical Repair Questions? Ask an Electrician for Answers ASAP
Welcome. My name is XXXXX XXXXX would be glad to assist.
The calculation is very good on the distance and wire size. I show approx 2.9% drop
Will you only be using 30 amps 240 volts at the location? Or will yu have 120 volts needed?
If you will use 120 and 240 at the 30 amp panel, you will need the 4 wire feeder.
If only using 240 volts and no 120 volts, you can use the 3 wire feed
I will have 1 circuit that is 15A, 240V to power a 3/4HP pump
Ok, then just a 3 wire feeder is good then. You still do need a ground rod at the location to tie into the ground at the panel as well.
I will also have one or two lighting circuits, 15A, 120V, and one or two receptacles, 20A 120V
Ok, then you need 4 wire feeder
Neutral needs to be 2/0 as well, it will carry the return current, prefer to be on the safe side at that distance.
Especially with all the 120 volt items possibly operating
Ground on 30-60 amp circuit Table 250.122 is required to be #10 copper or #8 aluminum
OK, so I've already ordered the 2/0-2/0-1 cable, so I can use the 1Ga for the ground, and now I have to buy a 2/0 single for the neutral?
You can use the #1 as the ground if you wish, overkill , but you already have it
How can I connect the 2/0 conductor to the breaker? It only will fit a #2 Ga?
The #1 would actually carry the full unbalance of the system it appears for the neutral it is good for 20 amps
That is always the issue when running such a distance. Usually mount a disconnect outside and run the normal 30 amp from the panel to the disconnect and then the larger cable will fit in the disconnect lugs
OK, so I was trying to avoid having to mount the outdoor disconnect on my metal building, but it makes sense to do it as you say. Now, what if I mount the disconnect on the outside wall, but it is 60 ft. away (on opposite side of building from the 200A panel) What size conductors would I need to connect between the panel and the disconnect? (I use EMT conduit inside the metal building)
Standard #10 should fair well. The drop will be at the disconnect to the panel.
If you have the resource, you could bump it up to #8 which is a step above. That would be you call
OK, just one more question: the trench should be 24-30" deep? If it crosses under a driveway (gravel farm lane), does it need to be run thru conduit? What size?
you can stay the standard 24" and no conduit is needed.