ECN Electrical Forum - Discussion Forums for Electricians, Inspectors and Related Professionals
ECN Shout Chat
ShoutChat
Recent Posts
Switched Receptacles -Top or Bottom?
by gfretwell - 07/28/21 10:06 PM
Lowes Selling this fan
by timmp - 07/25/21 10:58 PM
How's all our Non-US folks doing?
by djk - 07/23/21 09:13 PM
Do You Travel?
by Bill Addiss - 07/20/21 04:26 PM
Backup Generator Done Right
by timmp - 07/18/21 12:20 PM
New in the Gallery:
February, North East Indiana
February, North East Indiana
by timmp, July 25
Red Green would be proud
Red Green would be proud
by timmp, July 25
Who's Online Now
0 members (), 15 guests, and 15 robots.
Key: Admin, Global Mod, Mod
Previous Thread
Next Thread
Print Thread
Rate Thread
#34497 02/13/04 09:16 AM
Joined: Dec 2003
Posts: 15
R
Rob Offline OP
Member
Outdoor hot tub on a deck.
It is a replacement tub, I was
asked to wire it in. The original wiring
has a "bond" wire from the pump frame to a
ground rod under the deck. The panel box is located on other end of house. There is
a continuous ground to the main panel and a
2 pole GFCI breaker. (Is this in the NEC ? )
I am not sure I should rewire the new one to it again. Thanks for any info.

#34498 02/13/04 02:50 PM
Joined: Dec 2003
Posts: 751
E
Member
In the 70s and 80s a lot of folks did not understand grounding. Many inspectors required them to and many electricians would install ground rods at all outdoor thingies (pools, hot tubs, light poles). We know better now, but you will still see it happening. Ignore it. Drive it out of sight. Just make sure you have a low impedance path back to the OC device, and all that should be bonded is.

Earl


Earl
#34499 02/14/04 01:07 AM
Joined: Jun 2003
Posts: 681
P
Member
As Earl has mentioned, there is bonding and grounding required for pools and hottubs, and it seems that a lot of people have trouble understanding the difference between bonding the hottub and grounding it.

Pierre


Pierre Belarge
#34500 02/14/04 09:06 AM
Joined: Sep 2003
Posts: 650
W
Member
I know that you don't need a ground rod in order to properly bond a piece of equipment to the building electrical system, that 'grounding' a piece of equipment without bonding it to the OCPD panel is both wrong and dangerous, and that once you have bonded back to the panel, you will have also 'grounded' the electrical equipment.

However, is there any reason _not_ to use this extra ground rod that happens to already be buried in the ground at the location? If this hot tub were in a separate out-building with a subpanel, I presume that the subpanel would _require_ grounding electrodes, connected to the equipment grounding conductor, but isolated from the neutral.

-Jon

[This message has been edited by winnie (edited 02-14-2004).]

#34501 02/14/04 09:55 AM
Joined: Jan 2003
Posts: 4,391
I
Moderator
250.54 would allow the use of the "extra" ground rod and I can not think of any reason it would do more harm than good.

I also do not see what safety it will add so IMO using it is a waste of stock.

However if this outdoor hot tub has more than one circuit feeding it or is fed by a feeder you may be required by 250.32(A) to install and use a ground rod. [Linked Image]


Bob Badger
Construction & Maintenance Electrician
Massachusetts
#34502 02/14/04 11:42 AM
Joined: Feb 2003
Posts: 687
A
Member
To correctly utilize the hot tub ground rod would it not require a larger ground wire? Then to fit the larger wire a bigger pipe.

Example:

A 50 Amp hot tub I would run a # 8 equipment ground to the first (outside) disconect. Then a # 10 from that disconect to the panel.

To use the ground rod by the tub on say a 200 a service it would require a # 4 the entire distance.

I don't know if there is something in the NEC but around here the branch circuits would never be run with the buildings grounding system.

What would happen to the branch circuits or hot tub in the same pipe as the grounding system if it took a surge from lighting? I think it could induce some voltage to the other circuits.

#34503 02/14/04 11:55 AM
Joined: Jan 2003
Posts: 4,391
I
Moderator
Hi Active as this ground rod is considered a supplementary ground rod many of the regular requirements do not apply.

Quote
250.54 Supplementary Grounding Electrodes.
Supplementary grounding electrodes shall be permitted to be connected to the equipment grounding conductors specified in 250.118 and shall not be required to comply with the electrode bonding requirements of 250.50 or 250.53(C) or the resistance requirements of 250.56, but the earth shall not be used as the sole equipment grounding conductor.

In short if you choose to install this supplementary electrode you simply connect it to the EGC wherever you want with whatever size wire you want.

Unless there is local amendment I do not see how your inspectors could fail this.

Bob


Bob Badger
Construction & Maintenance Electrician
Massachusetts
#34504 02/14/04 01:46 PM
Joined: Dec 2000
Posts: 4,287
Member
The use of the words "supplemental" and "supplementary" might throw some off.
A supplemental electrode is one that's required by 250.53(D)(2) to augment an underground metallic water line at a service.
A required supplemental electrode still doesn't have to be connected with a conductor larger than a #6 See250.53(E).

A supplementary electrode is, as iwire says, just that. 250.54, and is permitted

#34505 02/14/04 10:35 PM
Joined: Feb 2003
Posts: 687
A
Member
Thanks Iwire and electure. I did forget you could use a #6 for the rod. I tend to just use the extra from the water pipe run because the rod is never too far.

#34506 02/15/04 08:20 AM
Joined: Jan 2003
Posts: 4,391
I
Moderator
Quote
The use of the words "supplemental" and "supplementary" might throw some off.

Why would that be confusing. [Linked Image]

Thanks Scott that is a very good point, the "supplemental" rod is subject to the rules of other electrodes. [Linked Image]

Bob


Bob Badger
Construction & Maintenance Electrician
Massachusetts

Link Copied to Clipboard
Featured:

Tools for Electricians
Tools for Electricians
 

* * * * * * *

2020 Master Electrician Exam Preparation Combos
2020 NEC Electrician
Exam Prep Combos:
Master / Journeyman

 

Member Spotlight
CDS
CDS
Nicholson Ga
Posts: 34
Joined: June 2006
Top Posters(30 Days)
timmp 8
Rachel 4
djk 2
Popular Topics(Views)
281,584 Are you busy
215,222 Re: Forum
202,061 Need opinion
Powered by UBB.threads™ PHP Forum Software 7.7.5