RIVETER

You are talking about an egc, and you are right.

darren79

Subpanels would be fed with a bond. If someone was running a sub panel feed and decided to use a ground rod instead of the bond from the service you will still need to run a bond there so if someone did something stupid like cut the cable or dig up the pipe there would be a bond in the pipe. In the sub panel the bond would be capped off and not connected to anything, at the service the bond would have to get bonded to the grounding conductor. If that makes any sense to anyone.

xlink

Similar rules but different terminology. If you run a circuit with a bonding conductor to a sub panel or any other device you can tie the panel frame (not the neutral) to a ground rod. You might do that if you take a circuit to a building that has a ground grid.

That's wrong. If a hot faulted to ground and the rods don't conduct enough to trip the breaker, it would be an expensive way to create global warming. Besides that, you would have voltage to ground off the neutral and 240 from the other hot to ground.

You can't have everything. Either limit the voltage to ground to 120 volts or eliminate current on the ground conductor. Limiting the voltage to ground is safer.

sprdave

So you're saying a bond wire is always required to be ran with feeders?
I can understand what you're describing but didn't know that was required.

Can anyone confirm or provide a code rule to refer to?

I'll have to look closer now it has my curiousity, but I think there are multiple places at my parents' where there is no bond. Done by electrical contractors and inspected by ESA.

If there is a main service into a shop, to a splitter, with disconnects feeding other buildings, would those feeds require a bond wire?

Apparently I cant use as examples, work done by other contractors with like 30 years experience, inspected by ESA.....with these deficiencies Im finding.

It would be nice to ask an inspector about stuff like this...But the last time I saw one (one of the only times), at my parents, He didn't want to talk, and I had to "drag" Him from His car to address some deficiencies that I knew about that the electrical contractor had (not) done....which He wouldn't have found as He wasn't planning on leaving His car, instead charge my parents like $500 for "inspection"...grrrr

darren79

Obviously if your running tech cable or nmwu you will already have a bond in the cable.

If you go into section 12 and look at the different type of conduit, any non metallic conduit has this rule

Provision for bonding continuity

A separate bonding conductor shall be installed in "type of conduit" in compliance with 10-404.

A few months ago I was doing something similar to this and the inspector brought up the issue of bond in a PVC pipe. Working at a place where they were putting up a new building. We went from the CSTE to a fuseable disconnect with PVC, from the disconnect we took a pipe to the new building for a panel. The inspector made us put a bond from the disconnect to the CSTE but not tie it onto the ground lug in the CSTE.

The disconnect was grounded via the grounding conductor inside the building and if we were to put it under the lug in the CSTE we could have created multiple paths for ground. I wasn't paying attention when he was talking about it so I could be incorrect on it. The bond was connected in the disconnect and ran through the pipe for the sole purpose of having a bond in the pipe.

xlink

I hate it when rules are applied in a way that makes them silly. It makes it look like the inspector understands the rules but not the concept. Some electricians put their overhead services in pvc. wouldn't it look silly to have an extra wire sticking out the top of the service that wasn't allowed to be connected to anything?

darren79

Overhead service would be bonded by the neutral would it not? Anybody know the rule for that, I know it is in section 10 but can never find it.

oliquir

what if it is a 600V service without a neutral, does a bond wire is absolutley needed?

sprdave

What about underground service in PVC?

darren79

10-624(2)
The grounded service conductor on the supply side of the service disconnecting means shall be permitted to be used for bonding to ground the metal meter mounting device and service equipment.

Not sure if that would cover the bond in a pvc underground service.

xlink

I chose a poor example, but I appreciate that you found the rule. I didn't know there was a rule about that.

I agree with the code that the PVC is a very poor bond. It isn't nearly as good as EMT, so it needs bond wire to bond the equipment that it feeds. However, if it feeds a service that's going to be grounded, it seems a waste of resources to include a bond wire that is intended to be unused.

RIVETER

You are correct. The EGC, equipment grounding conductor, bonds all of the metal components to all other metal components of an electrical system . It is ONLY at the service that the EGC is physically connected to the neutral.

sprdave

Okay for interest sake, I experimented with this subpanel that has no bond with the feed and the neutral not bonded (maybe not the most ideal thing to do )
Checked for continuity between neutral and ground and got resistance (like 40ohms I think), so put in a 15A breaker connected a piece of 12ga from it to the ground bar in the panel, turned it on, and yep 4amps........
(It is about 100 feet from the main panel, or the transformer pole)

So Im thinking I should find a scrap piece of 6ga and stick it from the neutral bar to ground bar, right? Its fed from a 100amp breaker with 2ga aluminum.


And I was looking at my parents' chicken barn to get a picture of how it is done......but I don't think it's right

The barn holds something like 8000 laying hens in a cage system of 100' rows with metal frames, feed troughs, motors, belts, etc.
It is fed from a separate barn, with a 60amp breaker, 6/3 nmwu underground about 200' long, into a switch on the outside of the barn. In the switch the bond from the nmwu is connected to the ground bar, as well as a 6ga? which runs in the pvc feed into the barn. Where it connects to the ground in the transfer switch along with a bond to the 100amp panel, where it connects to a ground bar. The bonds leaving the panel are one 6ga to the propane line, and multiple 14 and 12ga in the pvc runs to the motors, etc.

Nowhere do I see any sign of a ground electrode, or any separate (other than the motor runs) bond to the cages, or any bond to neutral, and the bond is connected through from the other barn. My dad's response is it was done by a well experienced electrician and inspected closely by ESA twice in less than 10 years, so it has to be right

So is there any reason it would be right without the ground electrode, bond to frames of cages, etc?? Chickens not considered livestock? (although it had cows 10 years ago) Im just puzzled

Cujo

You don't need a bond for most equipment to work, its for safety. I always thought once per service as well but maybe im wrong after reading 10-208a.
Relevant rules I think:
10-024 (1)c
10-208
10-624

Seems like your dad's electrician got a ground from a grounding electrode in the other barn. If they are supplied off of the same service I see no problem, except for the livestock issue it seems.

10-204
10-504

crosport

Any building that houses livestock requires it's own ground electrode and the neutral has to be bonded to that electrode.No exceptions! Any ground wire in the N.M.W.U. is not allowed to bond the panel in this case.If this undergrnd. sub feed was in p.v.c. no bonding conductor should be required either.