Electrical power to pole shed

A sub panel in the same building as the main distribution panel requires 4 wires run to it and the neutral / ground bond left open in the sub panel.

A sub panel in a detached building only requires 3 wires, the two hot wires and a neutral. The neutral is bonded in the sub panel along with the required ground rods at the outbuilding. In this situation there are not supposed to be any other metallic connections between the main and detached building, no phone lines, water lines etc.

Otherwise 4 wires are needed between main and outbuildings and neutral and ground bonds left open at the sub panel but a local ground rod is still required at the outbuilding and it is tied to the ground bus of the sub panel along with the ground wire from the main panel.

You can always tie as many grounds as you like to the ground system in any case anywhere.
It is only sometimes that the ground and neutral are not to be bonded together. I.e. with 4 wire sub panel connections.

Regards
Gary

They can wire anything - just depends how much you need to spend on the armor & ground & so on.

--->Paul

That means you would run 4 wires to the Sub Panel (if you want both legs of 120 as you stated) being 2 Hots (L1 & L2 Red & Black),,,,, a Neutral (White Grounded Conductor) and an Equipment Ground (Green or Bare Grounding Conductor).

If you plan to direct bury it simply use type UF (Underground Feeder) wire. Since the run is 110 feet and you wanna use 20 amp branch circuits, I would use 10 Gauge Wire minimum to lessen voltage drop, that would be 10/3 with ground (4 conductor) Type UF Cable.

Sooooo ooooo to answer your question NOOOOO O you DO NOT use another ground rod at the shed and there at that Sub Panel you have seperate and isolated Neutral and Equipment Ground Busses.

Note, there are NEC exceptions as far as sub services to agricultural and outbuildings and additional grounding electrodes such as driven rods etc whereby you might get by with running 3 instead of 4 conductors, it has to do with maintaining the Equipment Ground Buss at the same potential as mother earth so when Bossy the cows nose touches the bonded to Equipment Ground Buss metal frame of say an automatic waterer, its potential is the same as mother earth so she dont get a shock.

DISCLAIMER Im long retired as an Electrical Engineer and am NOT up on the NEC as I once was and not familiar with the exceptions regarding service to sub panels for agricultural or remote outbuildings whereby you might get by running 3 versus 4 conductors to the remote location and re establshing another grounding electrode such as another driven ground rod etc as you asked,,,,, ,, sooooo ooooo you best check with your local building authority or agency as many of these practices are governed not only by the NEC but by the local governments and electrical inspectors etc.

PS At your existing Main Service Panel you would serve the Sub Panel with a 2 pole 240 volt (tied) 20 amp circuit breaker, that way if one leg would have a fault, the breakers tripping would cut power to BOTH legs L1 & L2.

Best wishes n God Bless

John T (Long retired and NEC rusty EE)

I was thinking everything needed the 4 wire setup you describe.

When the pros rewired my farm, it was 3 wires to every building, with a ground rod driven at every box/building.

I was surprised. Guess I must be in the ag variation thing. Inspector was fine with everything, actuially got bored & don't think he inspected 1/2 of the buildings.

A person might want to find out which way the local inspecor prefers it for the particular type of building you are putting up.

--->Paul

Take care yall

John T