Salty Cajun Folks With Electrical Knowledge

[Reggoh]

Originally Posted by keakar

last I was aware, the electrical residential wiring code called for only 3 wires, two main wires and a ground wire (often slightly smaller sized) so this is why everything 220v "inside" the house is running off or 6/2 with ground or 8/2 with ground romex.

for safety they use an extra main wire connected to the exterior panel ground lug is why you need 3 main wires when running under ground out to a shed or separate garage? its just extra safety in case there is a problem with the grounding rod for the shed or garage.

The appliances in your home that you are talking about (hot water heater) are dedicated 220v and only require 2 hots and a ground... a sub panel in a garage or shop needs the 4th wire for a neutral so you can run 120v.

220v needs 2 hots and 1 ground
120v needs 1 hot, 1 neutral, and 1 ground

If you need help send me a PM... I'm not an electrician but I did stay at a Holiday Inn express last night.

(Just kidding... I am an industrial electrician so some of the residential guys may know a little more about code than I do but I'd be glad to help if I can)

[keakar]

Originally Posted by Reggoh

The appliances in your home that you are talking about (hot water heater) are dedicated 220v and only require 2 hots and a ground... a sub panel in a garage or shop needs the 4th wire for a neutral so you can run 120v.

220v needs 2 hots and 1 ground
120v needs 1 hot, 1 neutral, and 1 ground

If you need help send me a PM... I'm not an electrician but I did stay at a Holiday Inn express last night.

(Just kidding... I am an industrial electrician so some of the residential guys may know a little more about code than I do but I'd be glad to help if I can)

well yes but in 110v the neutral and grounds are both connected to the same ground bar feed by one common main ground wire so as far as feeding the panel you only need 2 hots and 1 ground weather you run 220v or 110 off of it. I know they changed the rules on indoor appliances so you run 3 conductor plus ground to driers and stoves and such so you have two dedicated grounds for 220v just like you have for 110v but not to attics or exteriors boxes like central heaters or outside power to a/c.
as far as main wires feeding the panel goes, when a shared meter and breaker panel is used to power an exterior building, I am only aware of using 3 conductor plus ground so that the third conductor acts as a main grounding wire in case the grounding rod for this exterior building should fail.

but I haven't done residential wiring in a long time so im sure they may have changes to things I am not aware of.

I do notice the large amount of tools he wants to run, while he says only one at a time, he might be better with a separate power supply NOT feeding off the same meter and panel as his house because the "potential" to overload the power supply coming through the meter and main house panel is there. if he were careful he would be fine as long as he doesn't overload it. I just don't know what the limits are before code requires a separate meter or not to be honest.

he really does need a residential electrician to asses if he has unused power to run everything in the shop he wants to and to determine the distance involved to properly make decisions rather then guys like us that know electricity but may not be aware of all the latest codes and requirements. I used to do residential electrical for new houses for 20 years and it felt like they come up with new rule changes for it every few years. at this point, everyone in this thread is just assuming he has the power available to tap into his house panel but just because there is an open breaker slot doesn't mean you wouldn't be overloading the panel by adding it.