2 amateur electricians ...

[theoldwizard1]

... trying to wire a 240V GFCI/disconnect for a hot tub.

The "other guy" insisted that there need to be a bare ground wire from the box to a ground rod, even though there are 4 wires coming from the main (40+ year old main with combined neutral/ground bar).

Conveniently there is a ground rod very near (only one, and likely not to current code length) that I think is connect to the common neutral/ground bar in the main.

 

[purplezr2]

I don't know Michigan Code.

When I looked it up for my state-MN I was allowed to run 4 wire feeder from my Panel to my sub-panel with no ground rod. This applies for attached structures, which I assume yours is.

See this sticky by Wylie

 

[AntonLargiader]

Is this an outdoor tub with a GFCI breaker in a panel like this one, separate from the building?

https://www.homedepot.com/p/GE-60-Amp-GFI-Spa-Panel-UG412RMW260P/100567181

Or something else? Just curious, because you don't seem to be asking a question...

 

[theoldwizard1]

Yes, it is this one. It is physically mounted on the outside of the house <10' from where the tub will be located.

So from an NEC standpoint, is that an "attached structure" or a "detached structure" ?

 

[AntonLargiader]

Sounds attached to me, and I don't see anything GEC-related in article 680 Part IV.

 

[mm08822]

Yes, it is this one. It is physically mounted on the outside of the house <10' from where the tub will be located.

So from an NEC standpoint, is that an "attached structure" or a "detached structure" ?

neither.....it's equipment. You are providing a disconnect in a branch circuit for a piece of equipment.

It is not a service feeder to another building.

 

[AntonLargiader]

It is not a service feeder to another building.

But is it considered a subpanel? It has a breaker in it.

 

[Ji m]

Not to be the Debbie Downer,

but the only reason Pools and Hot Tubs have so much electrical code devoted to their installation is because doing it wrong can = floating bodies.

Hopefully you get some good advice here, or in person at the installation.

I'd want a qualified individual there on site if it was my hot tub.

Good luck.

 

[ard]

Man, Ive messed up a TON of pools and spas, and NEVER had a floating body.....

 

[Siegel1719]

Im going to go with its a subpanel. In michigan that means 4 wire feeder. Plus two ground rods at the panel. Always better to over do it. Also isolate neutrals and grounds in the new panel.

 

[sberry]

I believe the 4th wire needs to be insulated. It's been a while,,,, I have read this but there isn't a rod for the spa. The idea is to keep this as pure as it can be, no possible way to induce any voltage to this equipment not down insulated wires it's intended to be.
A rod may not hurt provided this is the sole piece connected to it, could reduce any step potential between it and the ground it sits on. As I said, it's been a while since I studied it and can't quite remember the particulars. But I think in the end no rod.

 

[theoldwizard1]

A rod may not hurt provided this is the sole piece connected to it, could reduce any step potential between it and the ground it sits on. As I said, it's been a while since I studied it and can't quite remember the particulars

It is NOT !

Image below shows no ground rod.

 

[Ji m]

Man, Ive messed up a TON of pools and spas, and NEVER had a floating body.....

lol!

 

[mm08822]

Im going to go with its a subpanel. In michigan that means 4 wire feeder. Plus two ground rods at the panel. Always better to over do it. Also isolate neutrals and grounds in the new panel.

He stated he is using a 4 wire feed. You only need the grounding electrode (2 rods) for a detached structure/building if you can't use the exception in 250.32.

Since a hot tub is equipment as defined in 680.2, it is not a structure. Hence the electrode requirement in 250.32 does not apply.

But is it considered a subpanel? It has a breaker in it.

What difference does it make if it is a sub-panel or a single branch circuit disconnect? As long as 4 wires are pulled to "it" and the egc is not bonded to neutral, all is good.



Adding a grounding electrode is going above and beyond the requirement which is fine. However, it has to be bonded to the existing electrode system.

 

[mm08822]

Man, Ive messed up a TON of pools and spas, and NEVER had a floating body.....

messed up or messed in???

 

[alfredeneuman]

The worst case of mistaken ground rods I've ever seen was when an Engineer called out separate rods in his blueprints for 50+ parking lot light poles.
He argued that they were separate "structures".

We finally (after days and days) convinced him to delete the rods from the plans.

 

[AntonLargiader]

What difference does it make if it is a sub-panel or a single branch circuit disconnect? As long as 4 wires are pulled to "it" and the egc is not bonded to neutral, all is good.

Curiosity on my part. My dad has a pool filter, away from the house, with a breaker disconnect like this next to it (I think the GFCI is on the house end of that circuit). If there was a shed around it, with a light and a convenience receptacle, it seems like it could be considered a detached structure needing ground rods on the subpanel. I don't know where the trigger point is for that. Hence my curiosity on whether this sort of thing is considered a subpanel.

 

[m32825]

Man, Ive messed up a TON of pools and spas, and NEVER had a floating body.....

Code reference: Caddyshack Baby Ruth

 

[sberry]

The worst case of mistaken ground rods I've ever seen was when an Engineer called out separate rods in his blueprints for 50+ parking lot light poles.
He argued that they were separate "structures".

We finally (after days and days) convinced him to delete the rods from the plans.

I have seen them for that and the explanation was,,,, that,,,, similar to a detached structure they would rather see a lighting strike to ground rather than have the conductors carry it back.

Adding a grounding electrode is going above and beyond the requirement which is fine. However, it has to be bonded to the existing electrode system.

I remember the discussion about this whole thing on a code forum way back. There was a bit of back and forth over it,,, wish I could remember the outcome.

It is NOT !

Don't blow a gasket, I tend to agree, I only mention a bit of the theory behind it.

 

[sberry]

I strayed, back to 250.54. This section permits a supplemental grounding electrode at the equipment, but the electrode must be connected to the equipment grounding conductor in the circuit to the equipment. A lot of mall lighting is installed this way. The supplemental electrode is bonded to the equipment ground of the light, and it provides added safety for lighting hits. A lot of the lightning energy will dissipate down the rod. Otherwise it would go back on the equipment ground in the circuit and since the insulation is only 600 volts, it causes a lot of damage to conductors.

I copied this from another forum. Its just a thought.

 

[dave*99]

I was required to use a same size separately insulated ground. I’m in NJ. It was a 4 wire 50amp circuit. So I pulled 4 conductors in conduit from the main service panel to the disconnect. No ground rod was needed.

 

[alfredeneuman]

sberry, The area that he wanted ground rods only has lightning about every 4 or 5 years, but it could be he comes from an area where lightning is a regular occurrence.

 

[mm08822]

Curiosity on my part. My dad has a pool filter, away from the house, with a breaker disconnect like this next to it (I think the GFCI is on the house end of that circuit). If there was a shed around it, with a light and a convenience receptacle, it seems like it could be considered a detached structure needing ground rods on the subpanel. I don't know where the trigger point is for that. Hence my curiosity on whether this sort of thing is considered a subpanel.

The trigger point is:
1) Building or structure and
2) More than one branch circuit (can be a multiwire)

My guess is the number of circuits implies size of the building or structure. A taller building more likely to get hit by lightning than a smaller one if was in same spot. Dunno??

 

[sberry]

sberry, The area that he wanted ground rods only has lightning about every 4 or 5 years, but it could be he comes from an area where lightning is a regular occurrence.

I understand.

 

[alfredeneuman]

I HAVE installed ground rods with parking lot poles on a new BMW dealership (2 stories with a rooftop parking lot) less than 500' from a 50,000 watt AM radio antenna, bonded to the rebar cage of the pole base and from there to the poles themselves.

The plans called for ground rods every 10' around the circumference of the >1000' building.
Every inch of the reinforcing steel (as large as 1") was welded, with a 3/0 bare copper run around the building cadwelded to the rods.
2/0 pigtails were cadwelded to the reinforcing steel, which in turn was cadwelded to the 3/0 surrounding the building.
Every bolt and nut in the place were tack welded, along with the steel conduit fittings.
It made for quite an expensive, impressive system.

 

[ard]

I HAVE installed ground rods with parking lot poles on a new BMW dealership (2 stories with a rooftop parking lot) less than 500' from a 50,000 watt AM radio antenna, bonded to the rebar cage of the pole base and from there to the poles themselves.

The plans called for ground rods every 10' around the circumference of the >1000' building.
Every inch of the reinforcing steel (mostly 1") was welded, with a 3/0 bare copper run around the building cadwelded to the rods.
2/0 pigtails were cadwelded to the reinforcing steel, which in turn was cadwelded to the 3/0 surrounding the building.
Every bolt and nut in the place were tack welded, along with the steel conduit fittings.
It made for quite an expensive, impressive system.

lol

Turns out it was a front for an NSA listening post....

 

[alfredeneuman]

It's radio station KNX in Los Angeles......
I've talked to folks in New Jersey and comes in clear as a bell there under the right atmospheric conditions

 

[ttpete]

I HAVE installed ground rods with parking lot poles on a new BMW dealership (2 stories with a rooftop parking lot) less than 500' from a 50,000 watt AM radio antenna, bonded to the rebar cage of the pole base and from there to the poles themselves.

The plans called for ground rods every 10' around the circumference of the >1000' building.
Every inch of the reinforcing steel (as large as 1") was welded, with a 3/0 bare copper run around the building cadwelded to the rods.
2/0 pigtails were cadwelded to the reinforcing steel, which in turn was cadwelded to the 3/0 surrounding the building.
Every bolt and nut in the place were tack welded, along with the steel conduit fittings.
It made for quite an expensive, impressive system.

That has more to do with the RF from the transmitter site. If any of the wiring is of a length that will resonate with the transmitter frequency, all kinds of nasty problems could arise.

 

[PoorOwner]

can someone confirm a full size ground is needed if something is for a pool / hot tub?
the last electrician installed 6 AWG for all 4 wires (insulated ground also) and I always thought you can do 10AWG ground for regular subpanel under 60 amps.

 

[sberry]

I don't think it needs to be upsized but might may need to be insulated. An insulated ground on a pool or spa would be a good thing, they don't want it shared with other equipment.

 

[dave*99]

can someone confirm a full size ground is needed if something is for a pool / hot tub?
the last electrician installed 6 AWG for all 4 wires (insulated ground also) and I always thought you can do 10AWG ground for regular subpanel under 60 amps.

I had to do same as your electrician did. Same size insulated ground for a hot tub. When I did the sub panel in the attached garage I was able to use 6/3 wg NM which has a smaller ground. The hot tub and sub panel requirements are different in NJ.

 

[NVSean]

I had to do same as your electrician did. Same size insulated ground for a hot tub. When I did the sub panel in the attached garage I was able to use 6/3 wg NM which has a smaller ground. The hot tub and sub panel requirements are different in NJ.

Check with your local building department inspection office. I just completed a 70’x42’x20’ detached garage that required 2 grounding rods, and then the inspector picked up that our existing pool equipment was more than 6’ from the main house and required it’s own separate grounding rod.
Lesson learned- once you start a new project connecting to existing structure, you open up everything to inspection again. Codes change, so check with your local inspectors office. We have frequent lightning strikes out here in the desert of Nevada.
Best of luck.
Sean


Sent from my iPad using Tapatalk

 

[alfredeneuman]

NEC 680.21 (A)

(1) General. The branch circuits for pool-associated motors shall be installed in rigid metal conduit, intermediate metal conduit, rigid polyvinyl chloride conduit,......... Any wiring method employed shall contain an insulated copper equipment grounding conductor sized in accordance with 250.122 but not smaller than 12 AWG

(The Code doesn't say that the ground wire has to be the same size as the phase conductors)