Jacuzzi and GFI

[Homeownerinburb]

A peak reading, clamp-on ammeter might help. If the motor has a plug to it, or it can easily be disconnected, I'd try that and then apply power. If it still trips the breaker, it's not the motor, it's the controller.

The "controller" meaning the brains that run the whole thing?

 

[Jadnashua]

The "controller" meaning the brains that run the whole thing?

Yes...divide and conquer. The motor is probably a fairly simple device, might be multispeed, but still a motor (pump). If the power stays on when it's disconnected, it's probably in the motor. If the breaker still trips, it's not the motor. You might do the same thing if there are heaters that you can disconnect to again, isolate what is the issue.

 

[Sponsor]

 

[Homeownerinburb]

Yes...divide and conquer.

Thanks, that is my friend's plan.

 

[Homeownerinburb]

Oh, and there almost certainly is a transformer in there stepping down the 240 to 120. Possibly everything but the heater runs at 120. That is my assumption until I see a schematic that says otherwise.

 

[Jadnashua]

It would be quite inefficient to use a 120vac motor run off of an internal transformer...if they needed 120vac, they'd have a neutral required, and get it from the mains. There might be a small transformer if there are any electronic controls as part of its power supply, but not a main power one for the motor/pump/heaters. But, a 240vac GFCI that had a neutral probably wouldn't work, and would trip. I'm not certain about how they're wired internally, but generally, they only look at two leads to compare the in/out power, and, if you have a neutral, you'd have to be monitoring that as well.

 

[Homeownerinburb]

It would be quite inefficient to use a 120vac motor run off of an internal transformer...if they needed 120vac, they'd have a neutral required, and get it from the mains. There might be a small transformer if there are any electronic controls as part of its power supply, but not a main power one for the motor/pump/heaters. But, a 240vac GFCI that had a neutral probably wouldn't work, and would trip. I'm not certain about how they're wired internally, but generally, they only look at two leads to compare the in/out power, and, if you have a neutral, you'd have to be monitoring that as well.

The jacuzzi is used, and came with two hots and a ground in the whip that was attached to it.

If you insist, then the pump motor could be 240v. I have not yet looked inside.

 

[Jadnashua]

Ground should NEVER be used as a power conducting lead...it is there for safety. So, since it has no neutral, expect everything is 240vac. Things like your electric dryer and stove often have 120vac components (light bulbs, etc.), so they need the neutral.

 

[Homeownerinburb]

Ground should NEVER be used as a power conducting lead..

Yes, I knew that.

Just like I know that in the dark old days it was indeed used on three wire stove wiring to dump the 120v load down to the common neutral/ground bus bar.

 

[Jadnashua]

Yes, I knew that.

Just like I know that in the dark old days it was indeed used on three wire stove wiring to dump the 120v load down to the common neutral/ground bus bar.

The code rules adopted in 1996 (twenty years ago) recognized that connecting the ground and neutral at multiple locations rather than just the main panel, created problems. Ground conductor should never be used as a current carrying conductor...it is there for safety...any conductor carrying current can have voltage develop across it by the internal resistance and create other problems in the system. Plus, in many circumstances, they allow the ground conductor to be smaller than the current carrying conductors.

 

[Homeownerinburb]

"The code rules adopted in 1996 (twenty years ago) recognized that connecting the ground and neutral at multiple locations rather than just the main panel, created problems."

Yes yes yes. Yet the fact remains that ranges sold today do not have cords wired in because 3 wire rather than 4 wire installations are the most common.

I've fitted a few ranges, and have yet seen a 4 wire configuration. It would be nice to magically introduce a neutral, but that is just not going to happen in most cases.

 

[WorthFlorida]

#8 wire requires nothing more than 40 amp breaker. For 50 amp #6 wire is required. I guess your friend got this 2nd hand tub because no one before could find the short or want to pay to have it fixed. It also must be old since it is a three wire, not four.
http://www.spadepot.com/wiring-hot-tub-spa.htm

 

[Speedy Petey]

Yes, I knew that.

Just like I know that in the dark old days it was indeed used on three wire stove wiring to dump the 120v load down to the common neutral/ground bus bar.

You are quite wrong about this. The ground WAS NOT used as a neutral in those cases. It was the neutral that was also used as the equipment ground.

Your misinterpretation of this type of older installation is unfortunately very common.

 

[Homeownerinburb]

#8 wire requires nothing more than 40 amp breaker. For 50 amp #6 wire is required. I guess your friend got this 2nd hand tub because no one before could find the short or want to pay to have it fixed. It also must be old since it is a three wire, not four.
http://www.spadepot.com/wiring-hot-tub-spa.htm

8ga Thhn is rated at 55amps.

It is a pretty recent tub, I've now seen the installation manual and it is indeed designed without a neutral, go figure. There must be a transformer in there for the lights and probably the control panel.

 

[Homeownerinburb]

You are quite wrong about this. The ground WAS NOT used as a neutral in those cases. It was the neutral that was also used as the equipment ground.

Your misinterpretation of this type of older installation is unfortunately very common.

I think it is a distinction without much of a difference.

The point is that the neutral and ground were both on the same wire, and this has long ago been determined to be undesirable and unsafe. Unhappily many older installations exist. And adding a conductor is difficult in most cases verging on impossible.

 

[Speedy Petey]

I think it is a distinction without much of a difference.

Wrong! There is a VERY big difference between a neutral and a bare ground wire.

The point is that the neutral and ground were both on the same wire, .....

Right, the NEUTRAL wire. Not the bare ground wire.

 

[Speedy Petey]

8ga Thhn is rated at 55amps.

Which is the 90 deg C column rating, which is meaningless for everything but derating purposes.

For a new THHN in conduit/raceway or MC application we would use the 75 deg C column since about the only thin rated 90 deg is the conductor itself. Most everything else in the circuit will be rated 75 deg.

For a NM installation we are limited to the 60 deg C column. But you already know this, don't you?

 

[Homeownerinburb]

Which is the 90 deg C column rating, which is meaningless for everything but derating purposes.

For a new THHN in conduit/raceway or MC application we would use the 75 deg C column since about the only thin rated 90 deg is the conductor itself. Most everything else in the circuit will be rated 75 deg.

For a NM installation we are limited to the 60 deg C column. But you already know this, don't you?

Yep. But it makes you wonder why NM is not sheathed in the same plastic as Thhn.

 

[Homeownerinburb]

Wrong! There is a VERY big difference between a neutral and a bare ground wire.

Right, the NEUTRAL wire. Not the bare ground wire.

Well, I did not specify either one originally.

You are on quite the jihad, aren't you?

 

[Speedy Petey]

You are on quite the jihad, aren't you?

I don't get it.

 

[Homeownerinburb]

I don't get it.

You are banging away on a point of your own making.