I have a detatched garage with a 3 wire subpanel off of a 90 Amp circuit in the mail panel. The conduit is not metal and is run under ground. I believe the 2 phases and neutral are #3 or #4 gauge but I haven’t measured them yet. I have done some research and have identified some problems with the sub panel.
1. There are 4 wire circuits connected and the sub panel has circuit grounds and nuetrals connected at the neutral bar.
2. There is no ground bar installed in the sub panel.
3. There is no ground from the main panel to the sub panel.
Other info: there is metal water pipes connected to the garage. It is not connected to the sub panel.
The 3 wires to the sub panel are run through a 1” conduit.
There is a seperate 240v circuit ran to the garage through a parallel conduit that is 2in diameter. I do not need to keep this circuit. Possible route for ground?
The garage had many 240v circuits that can be disconnected from the sub panel. The actual load would be a 240v 50 Amp GFCI protected spa and 3- 20Amp 120v circuits. So I could reduce the size of the breaker in the main box feeding the sub panel.
My goals are to connect a grounded bus in the sub panel. Separate grounds and neutrals for all circuits down the road. Be sure the neutral bar in the sub is floating. Run a 50amp 240v to GFCI disconnect for spa.
Questions: Does the ground for the sub panel have to be run to the main panel? Would a grounding rod suffice? Is it possible to run a heavy guage ground through the existing 2 in conduit that is buried under the drivway if I empty it? Since the ground and phase and neutral would be roughly the same length would that meet code? Do I need to dig up each end of the conduit to push the wire through? If I were to lower the load on the sub panel could thinner wires be used thus making it possible yo push through the existing conduit? Thank you!
Any advice is greatly appreciate!
1. There are 4 wire circuits connected and the sub panel has circuit grounds and nuetrals connected at the neutral bar.
2. There is no ground bar installed in the sub panel.
3. There is no ground from the main panel to the sub panel.
Other info: there is metal water pipes connected to the garage. It is not connected to the sub panel.
The 3 wires to the sub panel are run through a 1” conduit.
There is a seperate 240v circuit ran to the garage through a parallel conduit that is 2in diameter. I do not need to keep this circuit. Possible route for ground?
The garage had many 240v circuits that can be disconnected from the sub panel. The actual load would be a 240v 50 Amp GFCI protected spa and 3- 20Amp 120v circuits. So I could reduce the size of the breaker in the main box feeding the sub panel.
My goals are to connect a grounded bus in the sub panel. Separate grounds and neutrals for all circuits down the road. Be sure the neutral bar in the sub is floating. Run a 50amp 240v to GFCI disconnect for spa.
Questions: Does the ground for the sub panel have to be run to the main panel? Would a grounding rod suffice? Is it possible to run a heavy guage ground through the existing 2 in conduit that is buried under the drivway if I empty it? Since the ground and phase and neutral would be roughly the same length would that meet code? Do I need to dig up each end of the conduit to push the wire through? If I were to lower the load on the sub panel could thinner wires be used thus making it possible yo push through the existing conduit? Thank you!
Any advice is greatly appreciate!
