non grouned rx wireing furnace

[ddellin]

Does the code allow a connection to a grounded water pipe system and a non grounded furnace to ground the furnace?

 

[dirkhats]

Re: non grouned rx wireing furnace

Yes.

(C) Equipment Grounding Conductors Smaller Than 6 AWG Equipment grounding conductors smaller than 6 AWG shall be protected from physical damage by a raceway or cable armor except where run in hollow spaces of walls or partitions, where not subject to physical damage, or where protected from physical damage.

 

[don_resqcapt19]

Re: non grouned rx wireing furnace

If you are wanting to get an equipment ground to the furnace, then the answer is no. The EGC must be run with the circuit conductors.
Don

 

[BruceH]

Re: non grouned rx wireing furnace

Don, I believe there is an exception for this allowed for existing installations only. I don't have the book here at home right now but I remember reading it. It allows the equipment grounding conductor to be run separately for existing installations that are ungrounded.

 

[curt swartz]

Re: non grouned rx wireing furnace

Don, if this is an existing branch circuit 250.130(C) would allow the EGC to be run separately from the circuit conductors.

250.130 Equipment Grounding Conductor Connections
Equipment grounding conductor connections at the source of separately derived systems shall be made in accordance with 250.30(A)(1). Equipment grounding conductor connections at service equipment shall be made as indicated in 250.130(A) or (B). For replacement of non?grounding-type receptacles with grounding-type receptacles and for branch-circuit extensions only in existing installations that do not have an equipment grounding conductor in the branch circuit, connections shall be permitted as indicated in 250.130(C).

(C) Nongrounding Receptacle Replacement or Branch Circuit Extensions The equipment grounding conductor of a grounding-type receptacle or a branch-circuit extension shall be permitted to be connected to any of the following:

(1) Any accessible point on the grounding electrode system as described in 250.50
(2) Any accessible point on the grounding electrode conductor
(3) The equipment grounding terminal bar within the enclosure where the branch circuit for the receptacle or branch circuit originates
(4) For grounded systems, the grounded service conductor within the service equipment enclosure
(5) For ungrounded systems, the grounding terminal bar within the service equipment enclosure

 

[BruceH]

Re: non grouned rx wireing furnace

Yeah that's the one. Thanks Curt.

 

[redfish]

Re: non grouned rx wireing furnace

(1) Any accessible point on the grounding electrode system as described in 250.50

Is this grounded water pipe part of your grounding electrode system? If it is not than 250.130 (C)(1) doesn't apply.

 

[benaround]

Re: non grouned rx wireing furnace

Actually it's not a branch circuit extention and it's not a recpt.?

frank

 

[charlie]

Re: non grouned rx wireing furnace

Besides that, the water pipe is part of the grounding electrode system only within five feet of the point where it enters the building if the water pipe is a grounding electrode.

 

[redfish]

Re: non grouned rx wireing furnace

--------------------------------------------------------------------------------
Actually it's not a branch circuit extention and it's not a recpt.?

frank

Good call Frank.

Besides that, the water pipe is part of the grounding electrode system only within five feet of the point where it enters the building if the water pipe is a grounding electrode.

--------------------
Charlie Eldridge, Indianapolis, Utility Power Guy

The last sentence of 250.52(A)(1) prohibits the use of that portion of the interior metal water piping system that extends more than 5 ft beyond the point of entrance into the building to interconnect grounding electrodes and the grounding electrode conductor, because there are concerns over the use of nonmetallic piping or fittings causing an interruption in the interior electrical continuity of the metal water piping. The exception to 250.52(A)(1), however, permits this practice, provided there is qualified maintenance and the entire length of the water piping used as an electrode is exposed. This 5-ft limit also applies to the replacement of nongrounding receptacles with grounding-type or branch-circuit extensions in accordance with 250.130(C). See the commentary following 250.130(C) and the illustration that accompanies that commentary, Exhibit 250.49.

I can't leave Charlie out, good call Charlie.

[ August 14, 2005, 10:55 PM: Message edited by: redfish ]

 

[dirkhats]

Re: non grouned rx wireing furnace

While I agree Charlie is correct for the 5' inside the house as part of the grounding electrode system as per today's code. Most likely a house wired without the equipment grounding conductor usually used the entire water pipe system as their grounding electrode system. From the service disconnect, they went to the nearest cold water pipe. If that is still active (and the service has not been upgraded) then the nearest cold water pipe is still part of the grounding electrode system and could be used. This may not be the best practice since one upgrading the service may change this and not be aware that another has attached to the water pipe. But can it be done and compliant? I still say yes.

 

[BruceH]

Re: non grouned rx wireing furnace

The water pipe issue aside, I was also referring to 250.134 regarding equipment fastened in place. This exception also seems to allow a equipment grounding conductor ran independent of the circuit conductors. 2002 book, haven't got the new one.