[mwr]

Doing some work for my Pastor, nice fella. He has a peculiar situation with his GEC that is serving a subpanel.

The insulated conductor is ran in 1/2" PVC (like I am used to doing at work) but goes into a 1900 box and then the rest of the way in 1/2" emt (not used to doing at work!). So I assume it needs to be bonded as it enter the enclosure.

Do I use a 1/2" grounding bushing (non threaded for emt?) Or someone at work said he has seen grounding locknuts which I have never seen and cant picture?

Thanks!

 

[chicken steve]

I'm confused as to why a subpanel needs a GEC mwr.....:001_huh:~CS~

 

[Maple_Syrup25]

retro fit ground bushing!

 

[220/221]

Technically, both ends of the conduit need to be bonded which turns into a major PITA . Take it apart and lose the EMT....or just leave it.:whistling2:

If lightning hits, there will be far greater problems :laughing:

I'm confused as to why a subpanel needs a GEC

Detached structure?

 

[Cl906um]

Grounding locking nuts have angled piercing screw. I am not one to look up pics for you cause that takes away from family time.

 

[RIVETER]

Doing some work for my Pastor, nice fella. He has a peculiar situation with his GEC that is serving a subpanel.

The insulated conductor is ran in 1/2" PVC (like I am used to doing at work) but goes into a 1900 box and then the rest of the way in 1/2" emt (not used to doing at work!). So I assume it needs to be bonded as it enter the enclosure.

Do I use a 1/2" grounding bushing (non threaded for emt?) Or someone at work said he has seen grounding locknuts which I have never seen and cant picture?

Thanks!

In my opinion a gec should be run through either/or method but not in a combined system as you describe. If the gec is carried through a NON-COMPLETE metallic piping system the pipe, itself can become...or actually is a parallel path for "strike" current. The inductance setup at the point where the pipe ends and picks up at the rod can create as much as a 75 percent restriction TO the strike current delaying the energy trying to get to the earth. It IS going to get there but will be involved with the service for a longer period of time possibly causing more damage. IMO

 

[mwr]

What does our friend the NEC say about combined raceways as I describe?

 

[wendon]

What does our friend the NEC say about combined raceways as I describe?

No No No No No Bad!

 

[Pete m.]

I'm with CS... is this sub-panel in a separate structure?

Pete

 

[360max]

Technically, both ends of the conduit need to be bonded[/B] which turns into a major PITA . Take it apart and lose the EMT....or just leave it.:whistling2:

If lightning hits, there will be far greater problems :laughing:




Detached structure?

code article please

 

[360max]

Technically, both ends of the conduit need to be bonded[/B] which turns into a major PITA . Take it apart and lose the EMT....or just leave it.:whistling2:

If lightning hits, there will be far greater problems :laughing:




Detached structure?

code article please

 

[220/221]

code article please

Sorry, I don't retain code articles. I learn by doing it wrong first :laughing:

I got tagged for a GEC in EMT and looked it up.

All I remember is if you use metal conduit, it had to be bonded at both ends, therefore it is much easier to use PVC.

Google says :

250.64
(E) Enclosures for Grounding Electrode Conductor. Ferrous (iron/steel) raceways, boxes, and enclosures containing the grounding electrode conductors must have each end of the ferrous metal raceway, box, and enclosure bonded to the grounding electrode conductor [250.92(A)(3)].


Pete says it too

 

[Pete m.]

code article please

(E) Enclosures for Grounding Electrode Conductors.
Ferrous metal enclosures for grounding electrode conductors shall be electrically continuous from the point of attachment to cabinets or equipment to the grounding electrode
and shall be securely fastened to the ground clamp or fitting.
Nonferrous metal enclosures shall not be required to be electrically continuous. Ferrous metal enclosures that are not
physically continuous from cabinets or equipment to the
grounding electrode shall be made electrically continuous
by bonding each end of the raceway or enclosure to the
grounding electrode conductor. Bonding methods in compliance with 250.92(B) for installations at service equipment
locations and with 250.92(B)(2) through (B)(4) for other
than service equipment locations shall apply at each end and
to all intervening ferrous raceways, boxes, and enclosures
between the cabinets or equipment and the grounding electrode. The bonding jumper for a grounding electrode conductor raceway or cable armor shall be the same size as, or
larger than, the enclosed grounding electrode conductor. If a
raceway is used as protection for a grounding electrode conductor, the installation shall comply with the requirements
of the appropriate raceway article.

Pete

 

[wendon]

code article please

250.64 (e)

 

[Awg-Dawg]

250.64 (e)

Too slow, Pete M. beat you to it.

Anyone want to give the readers digest version why you have to bond the metallic raceway?

 

[Pete m.]

Too slow, Pete M. beat you to it.

Anyone want to give the readers digest version why you have to bond the metallic raceway?

It's beyond my knowledge base but there is something to do with "choke effect". That's the best I've got.

Pete

 

[Awg-Dawg]

It's beyond my knowledge base but there is something to do with "choke effect". That's the best I've got.

Pete

I get that.

I just don't know what that means.

Theres not supposed to be current on it, so why would you need to bond it?

Maybe someone smart will tell us

Which happens more often than not.:laughing:

 

[Pete m.]

Maybe someone smart will tell us

I have seen the answer to this question probably many times... and I'm with you ... I will wait until someone who is actually smart to chime in.. paging Brian John, Big John, Zog, Jraef, etc...

Pete

 

[wendon]

I get that.

I just don't know what that means.

Theres not supposed to be current on it, so why would you need to bond it?

Maybe someone smart will tell us

Which happens more often than not.:laughing:

I've been beat by Pete!
I'm not all that smart but, like has been stated, if the metal conduit isn't bonded at both ends, it'll will be a "choke" in the event of a lightning strike.

This article somewhat explains it.
http://www.ecmag.com/section/codes-standards/guardian-ground

 

[Awg-Dawg]

if the metal conduit isn't bonded at both ends, it'll will be a "choke" in the event of a lightning strike.

All I am saying is if the EMT is bonded(I am sure it is) why does the GEC have to be bonded to it?

Im sure there is a reason, I am just looking for someone smart to tell me why:laughing: