Question for an electrician

[mikeinatlanta]

Just put in a wellhouse and well. Installed a sub panel. Four wires feed the panel with 8 gage for both hots and neutral with a 10 gage ground. The ground and neutral bars are not tied at the sub panel but are in the main panel.

The well installers used a three wire pump. They put the two hots to the breaker and the third wire to ground.


Question: Shouldn't the third wire to the pump go to the neutral bar and not the ground bar? I'm thinking the well installers did it wrong, but would rather fix it than call them back out.

Thanks

[frankeeski]

2 hots and a ground. Ground only gets bonded in the main service panel. They hooked it up properly.

[mikeinatlanta]

Thanks I'll leave it. Why wouldn't it go to the larger gage neutral bar? Makes me wonder why the neutral wire is even there, or why the ground wire isn't also 8 gage.

[PhilO]

Not an electrician, but the neutral allows a 120 volt circuit. AC power does not complete the circuit through ground it completes the circuit back to the power source. So the two prongs of 240 complete the circuit. Ground is a safety which is why it is always connected to the chassis and not the motor. That well pump will work just fine without the ground attached, it just is not safe. So if something fails and power is applied to the case, it goes to ground, not sit there waiting for someone to ground it by touching it. So not specifically needed for your specific situation but if you ever want to put a 120 circuit in that sub panel it is needed because without it you have no way to complete the circuit using only one side of the power supply.

[first time builder]

Arent the two buss bars connected thru the metal housing ?

[Papa]

Arent the two buss bars connected thru the metal housing ?

Definitely not. If this were the case, you'd get electrocuted any time to touched the housing. The buss bars are isolated by standoffs in the enclosure.

[frankeeski]

Thanks I'll leave it. Why wouldn't it go to the larger gage neutral bar? Makes me wonder why the neutral wire is even there, or why the ground wire isn't also 8 gage.

Primarily because it's not a neutral. A neutral is a circuit path to complete the circuit which isn't needed for a 220 circuit. The ground is only there for a short circuit path should something go wrong. The reason the neutral wire was probably run in the first place is a lot of people end up wanting to monitor their pumps. Most monitoring systems are going to require 110 volts. Also techs usually need a service outlet to plug in equipment when servicing the pump house.

[mikeinatlanta]

Ok I get it now. Never realized that 240v needed no neutral or ground in order for the motor to function. After a bit of research I understand the following: Please correct me if I'm wrong.

Although not safe, one could disconnect the ground wire to the pump and it would still run. Same for my air compressor that has no electronics. Classic 240v three wire (2 hot and ground).

Some 240V appliances also have 120v powered parts (timers and such). These require a four wire setup (2 hot, neutral, ground) in order for the 120v powered parts to function.

[first time builder]

Papa you are for sure correct what I meant was the grounding bars.

[Papa]

Papa you are for sure correct what I meant was the grounding bars.

No worries. I'm not an electrician myself, but I have wired a few 220v circuits in my home. I ran a sib panel to run all my finished basement electric from, and I've run 220v circuits for my compressor and my lift.

Dave

[frankeeski]

Ok I get it now. Never realized that 240v needed no neutral or ground in order for the motor to function. After a bit of research I understand the following: Please correct me if I'm wrong.

Although not safe, one could disconnect the ground wire to the pump and it would still run. Same for my air compressor that has no electronics. Classic 240v three wire (2 hot and ground).

Some 240V appliances also have 120v powered parts (timers and such). These require a four wire setup (2 hot, neutral, ground) in order for the 120v powered parts to function.

The only problem with your second point is that some 240 volt single phase equipment have built in 240-120 transformers, thus not requiring a neutral wire either. This is why they call it electrical theory. Kind of like "practicing" medicine. ;)