How do you comply with exception no.1 of 250.32(b)(1), requirement (2) for existing buildings supplied by feeders without an EGC? If you must also install a Grounding Electrode at the panel being supplied by the feeders, wouldn't that always create a continuous metallic path to the grounding system, because you must create one?
How do you comply with 250.32(b)(1) Ex no.1?
- Thread starter BenG
- Start date
- Location
- New Jersey
- Occupation
- Journeyman Electrician
Are you asking about a feeder to a separate structure that does not have an EGC? If so you would bond the neutral and run a GEC to the GES.
Wouldn't doing that no longer comply with the exception? Particularly, requirement 2 that states "There are no continuous metallic paths bonded to the grounding system in each building or structure involved."
- Location
- New Jersey
- Occupation
- Journeyman Electrician
The "continuous metallic paths" would be something like a metallic water pipe, phone line, CATV, etc. If none of those exist it is permitted to use an existing 3-wire feeder without an EGC and bond the neutral at the separate location. For a new install you'll need a 4-wire feeder.
I see. Follow up question then. Does this rule only apply to a separate structure? Would this apply to feeders on the load side of an outside Main Service Disconnect that's attached to the same building? The feeders are run in underground PVC underneath the building, which would be considered outside the building, and then stub up into a Main Distribution Panel inside the building. I would think that because they are no longer Service Conductors on the load side of the Main Disconnect, they become Feeder Conductors, and "250.32 Buildings or Structures Supplied by a Feeder(s) or Branch Circuit(s)." would apply?
- Location
- New Jersey
- Occupation
- Journeyman Electrician
Yes it (no EGC) applies to existing separate structures. It may also apply if what you're calling the main servcie disconnect is set up as the emergency disconnect, not service equipment and so marked. {230.85}
230.85 mandates emergency disconnects for residential applications. This is a commercial building. This disconnect is directly adjacent to the meter though. Even though it's not required to be one, you're saying if this Disconnect is considered and marked as an Emergency Disconnect, 250.32(B)(1) Ex no.1 may still apply?
Or just the standard practices, because the load side conductors of an Emergency Disconnect are still considered Service Entrance conductors?
Thank you!
- Location
- Chapel Hill, NC
- Occupation
- Retired Electrical Contractor
How would a grounding electrode conductor at a remote building create a path to the grounding system?
Because it bonds to the grounding system of the building being supplied. The requirement doesn't specify what grounding system, the supply side grounding system or the supplied side grounding system, it just says "no continuous metallic paths bonded to 'the' grounding system in each building or structure involved." Which I read as meaning either/or, or both.
Or is the Grounding Electrode not considered to be a " 'continuous metallic paths' bonded to 'the' grounding system" because it itself IS the bonding system?
wwhitney
Senior Member
- Location
- Berkeley, CA
- Occupation
- Retired
If you have two separate GESs at two separate buildings, with each building having a GEC connecting its main disconnect to its GES, that does not constitute a continuous metallic path between the buildings, as the earth is not metallic.
Now if you have only a single building with a single GES, then a feeder was never allowed without an EGC.
Cheers, Wayne
I see. In the scenario I described above, there is no EGC ran with the feeders. This was leading me to believe I could use the exception for 250.32(b)(1). However, it's sounding more like what I thought was a Service Disconnect outside, is, or should be if it isn't, considered, listed and marked as an Emergency Disconnect. This would then identify the load side conductors from the Emergency Disconnect as Service Conductors and not as Feeders. Removing the need to run an EGC in the conduit, as the bonding to the grounded conductor would take place at the Service Disconnecting means downstream of the Emergency Disconnect, inside the building.
pipe_bender
Senior Member
- Location
- Boston
- Occupation
- Electrician
On a commercial building the conductors after the first disconnect are feeders.
What you have is a old existing utility style Multi Grounded Neutral outdoor feeder this was allowed in up to the mid 2000's.
I know Emergency Disconnects are not required on Commercial installations. However, this Disconnect is rated as "Suitable for use as service equipment." According to 230.85(3) it can be used as an Emergency Disconnect, in reference to residential applications.
You're saying that even though it is not required, I could not use and mark it as an Emergency Disconnect because it's installed for a commercial application even if it's otherwise suitable to be one? Is there a code section that says Emergency Disconnects can only be installed on One and Two-Family Dwelling units?