Wiring new hot tub using old hot tub wiring

[phochief]

Replaced our old 240v hot tub with a new one, which also uses 240v for motors, heater, etc, and 120v for low amp LEDs and touch screen control panel.

Right now there are just three 6 ga wires at the subpanel near the hot tub. 6 ga Black, Red and green. The old tub only needed the two hot lines and the green ground wire. The new hot tub has connections for four wires, Line 1, Line 2, Neutral and Ground.

Our electrician said he can wire it using only the 3 existing wires without pulling a new white wire for Neutral from the Main Panel by using a 60 amp GFCI breaker at the hot tub subpanel. Somehow he connects the Black, Red and Green wires to the GFCI and winds up with four wires out, Black, Red, White and Green. I guess he's using the green wire to act as both a ground wire and a neutral by going through the GFCI breaker.

He's been an electrician for a long time and says this will work fine and will be safe. Is he right? Will what he's doing be good?

Thanks,
David

 

[James]

It would not be allowed in the U.K.
however, your local requirements may be different, I would say that a dedicated cable back to your panel would be a better solution and the gfci is something that should be installed on the circuit anyway.

maybe @Megawatt could give better guidance on what the local requirements are?

 

[phochief]

• It would not be allowed in the U.K.
• however, your local requirements may be different, I would say that a dedicated cable back to your panel would be
• a better solution and the gfci is something that should be installed on the circuit anyway.

I think he's trying to save me some $$$ by doing it this way. There will definitely be a GFCI breaker at the hot tub disconnect. He said it would be nearly impossible to pull the one wire from the Main panel through the exiting conduit and would be quite expensive to rerun the entire line. I just want to know if it is going to be safe?

 

[Lucien Nunes]

This is not safe. I believe it is a violation of article 250.6 as neutral current will be flowing via an equipment grounding conductor. The presence of the GFCI doesn't unfortunately overcome the inherent danger in using an EGC as a surrogate neutral. If a high-resistance or loose connection occurs in the ECG, the neutral current diverted into the tub ground will make the tub hot at 120V, shocking the occupants, but the GFCI will not trip. This is because the point at which the objectionable neutral current diverts to the tub ground is just upstream of the GFCI, therefore the GFCI is unaware of it.

As an alternative to re-running the circuit, if it really is that difficult, perhaps a 240-120V step-down transformer could be used to power the 120V components of the new unit?

 

[Megawatt]

Replaced our old 240v hot tub with a new one, which also uses 240v for motors, heater, etc, and 120v for low amp LEDs and touch screen control panel.

Right now there are just three 6 ga wires at the subpanel near the hot tub. 6 ga Black, Red and green. The old tub only needed the two hot lines and the green ground wire. The new hot tub has connections for four wires, Line 1, Line 2, Neutral and Ground.

Our electrician said he can wire it using only the 3 existing wires without pulling a new white wire for Neutral from the Main Panel by using a 60 amp GFCI breaker at the hot tub subpanel. Somehow he connects the Black, Red and Green wires to the GFCI and winds up with four wires out, Black, Red, White and Green. I guess he's using the green wire to act as both a ground wire and a neutral by going through the GFCI breaker.

He's been an electrician for a long time and says this will work fine and will be safe. Is he right? Will what he's doing be good?

Thanks,
David

My friend I hate to rain on your parade but what your electrician is doing is so wrong and could have deadly consequences. You need to make the decision to replace your old wiring and use four # 6 gage wires to your new hot tub. Installed on a 50 amp GFCI BREAKER. Please do not let your electrician do this with 3 wires. Good luck and hope you enjoy your new hot tub.