Underground RMC as an Electrode? pandoras box?

[hurk27]

OK I just know how we love to debate things, so here's one, I have thought about a few times but never could remember to post about it.

a few houses we do over on the beach the POCO requires us to provide a 2 1/2" RMC conduit to the property line for them to pull there feed to the meter in, many times it can be quit a run 70 to 120' or more, and we usually put it down about 3'

I got to thinking, since this would qualify as a GE, as per 250.52(A)(5), 250.50 would require us to use it as one of the required electrodes, and 250.62(E) requires it to be made continuous, and that both ends would theoretically be required to be bonded.
now for the most part we leave the other end exposed and put a locknut and bushing on it, how would one go about making it continuous? we do bond it at the meter, but I have never thought about it being used as an electrode.
POCO does not want any conductors in it that might hamper their pull.

Talk about a Pandora's box

heres another: a RMC run to an out building, which could qualify as a GE at both ends? if this is true then if we run a bare copper conductor in the ground as an EGC it would also serve as an GE?

Ok bed time, let ya's ponder it till tomorrow.

 

[benaround]

Wayne,

IMO, The conduit would be an electrode 250.52(A)(8), but is there a GEC in the conduit,

refering to 250.64(E) ?

Also, IMO, The pipe electrode in 250.52(A)(5) is pounded into the ground like a ground

rod , ie; 'not smaller than 3/4" trade size'.

 

[nakulak]

the beach ? in Indiana ? I must be missing something.

 

[iwire]

This conduit supplying the meter does not exist to the NEC.

 

[Pierre C Belarge]

This conduit supplying the meter does not exist to the NEC.

I agree with the utility side RMC.

The RMC supplying another building on the property may be a different issue.
If it contains conductors, I would say that it does not qualify as an electrode.

 

[iwire]

The RMC supplying another building on the property may be a different issue.
If it contains conductors, I would say that it does not qualify as an electrode.

How did you come to that conclusion?

 

[Pierre C Belarge]

250.52(A)(5) does not mention the pipe with conductors contained in the pipe.

 

[e57]

250.52(A)(5) does not mention the pipe with conductors contained in the pipe.

It also does not mentionit being one of the chapter 3 methods and any other conditional use - that said - it may/will act like one.... Unitll it rusts out - certain soils, or at most beaches there would be little left of it after not too long. (with water you would know it rotted away...)

 

[iwire]

250.52(A)(5) does not mention the pipe with conductors contained in the pipe.

It also does not mention that the pipe must be empty.

 

[hurk27]

the beach ? in Indiana ? I must be missing something.

Yes we have beaches, all along Lake Michigan oh and don't believe the song there is no beaches in Kokamo, to far south

This conduit supplying the meter does not exist to the NEC.

So technically there is no NEC on the drop pipe from the meter into the ground, here if we install it, it gets inspected just the wires in it are NTSC here since the POCO installs these. we have to strap it, and if PVC use sec:80 where it goes into the ground, and if RMC we have to use a bonding bushing, I agree this is ahead of the point that a service starts in article 230, but they will inspect it:roll:

I agree with the utility side RMC.

The RMC supplying another building on the property may be a different issue.
If it contains conductors, I would say that it does not qualify as an electrode.

I have to agree with others as to the code just doesn't address this.

And here is my thought, since the part of the pipe that is in the ground is the actual electrode, the pipe out of the ground is the GEC, since the pipe is bonded by it's connection to the electrode it is in fact meeting the "bonded on both ends" requirement, so bonding it in the meter via bushing or bonding lock nut would suffice.

The main thing here is or what I was getting at is what does the code treat this pipe as, if it meets the requirements of and electrode, I have never run into an issue with this but, I have had to use bonding bushing on the drop pipe before, even the ones that just go into the ground a couple feet.

If we look at how many underground runs of RMC we do on many jobs that could qualify as an electrode, which would mean they would have to be used as one as per 250.50? and all the requirement of bonding to follow. yikes

I would guess the official way out would be "if a pipe contains current carrying conductors it is now a race way no longer just a pipe? so maybe a new definition the defines this in 100? or an FPN in 250.52(A)(5)?

 

[benaround]

This conduit supplying the meter does not exist to the NEC.

Bob, I agree that the pipe and wire as a system does not exist to the NEC, but, could you

explain to me why 250.52(A)(8) would not consider this an electrode if (A)(1) - (A)(7)

were not present. Just for discussion sake!

 

[e57]

"Conduit" while it may be "pipe" is refered to as a "raceway" for the codes purposes is it not? Raceway is not mentioned as an electrode.

 

[benaround]

"Conduit" while it may be "pipe" is refered to as a "raceway" for the codes purposes is it not? Raceway is not mentioned as an electrode.

How about 'other local metal underground systems or structures' this is mentioned as an

electrode ?

 

[K8MHZ]

Yes we have beaches, all along Lake Michigan

That isn't occupied by a steel mill?

 

[hardworkingstiff]

It also does not mention that the pipe must be empty.

I think the conduit would not meet the driven depth requirements of 250.53(G), and the OP did not mention any rock interferance.

 

[infinity]

I think the conduit would not meet the driven depth requirements of 250.53(G), and the OP did not mention any rock interferance.

I agree. That pretty much ends the argument.

 

[iMuse97]

the beach ? in Indiana ? I must be missing something.

What you are missing is a very big lake(we have several of them around these parts:

http://www.weekend-getaways.org/blog/wp-content//indiana-dunes-1.jpg

 

[iMuse97]

I agree. That pretty much ends the argument.

There is no rock interference; it's all dune sand unless Wayne knows of a beach I'm unfamiliar with.

 

[hurk27]

I think the conduit would not meet the driven depth requirements of 250.53(G), and the OP did not mention any rock interferance.

Yep I think you found an out for any requirement by an inspector for using underground raceway as a electrode, and 250.52(A)(7) is not one of the required electrodes, as it stops at (A)(6).

(7)is just a optional electrode if a 250.52(A)(1) through (A)(6) doesn't exist.

And the fact that most don't bury RMC 30" deep, we do in this case because of the construction in the area.

But as far as 250.52(A)(7) goes it looks like if the pipe is 30" or deeper and has 8' or more in contact with earth, it could be possible that it can be used as an optional electrode, it seems the NEC is silent on the matter?

 

[hurk27]

There is no rock interference; it's all dune sand unless Wayne knows of a beach I'm unfamiliar with.

yep you are correct, as a mater of fact, most of this area is all old sand dunes of an ancient shore line of Lake Michigan, so we have sand everywhere.

and ground rods are usless around here, if you can get below 100 ohms without treatment your doing good.

if you ever get down around these parts look me up, or PM me and I'll give you my number