sub panel Help
I would like to wire a new sub panel for the back yard. I plan on running 4awg 120 ft in 1 1/2″ conduit. max load at any given time would be ~80amps. Questions:
is 4awg big enough?
do i need to ground the subpanel at the new location or route it back to the main?
I plan on mounting it in the counter space in the outdoor kitchen area. approximately 2 to 3 ft off the ground, do you see any problems with that?
Yes, #4 is big enough assuming you’re talking about copper, assuming you’re talking about individual conductors (not cable), assuming you have 75-degree terminations, and assuming you use an 80-amp breaker in the main panel.
If the subpanel is in the same structure as the panel that feeds it, then simply run four wires (two hots, one neutral and one ground) between panels. Do not install a new grounding rod. If the subpanel is in a different structure, you’ll need one or more grounding rods. The grounding wire between panels can be #8 copper.
The 1 1/2″ conduit is large enough, no matter what kind of wire you plan to run or what kind of conduit you plan to use.
Assuming you make it weather-proof and provide the code-mandated clearances around it, that should be fine.
Do a “demand load calculation” (google it) to determine if your existing service can support everything you have now plus this additional load. That’s probably not an issue if your service is now 200 amps.
When you said 80 amps, do you means 80 amps of 240 volts (19.2 KW) or 80 amps of 120 volts (9.6 KW)? 80 amps at 240 volts is a whole lot of power. If you meant 80 amps at 120 volts, then you are using larger wire than necessary.
