Of double-tapping and subpanels

[Bruce Thompson]

Hey guys I've got a question.

Regarding the first picture. Would this still be called double-tapping (using a lug instead of a breaker)? Or does it have another name?

Regarding the second picture. Is this what is meant when a subpanel has a white neutral bonded to enclosure and grounds?

Thanks in advance.
Bruce

[tdietrich1]

1. Yes, 'double tapping' can be used as a term here.

2. Don't know if there is a specific term, but I describe it as "non-isolation of grounded conductors from ground (bonding) system"

Now that I quickly, and humbly, answered your questions here are mine.

Photo 1:
- Under the same lug, are they different conductor material? Al and Cu?

Photo 2:
- Did you call out improper cable connectors? (cables coming through knockouts)
- Did you actually see a bonding strap/screw on that neutral bar?
- Feeder appears coming through a conduit, is the locking ring properly sized?

tom

[Bruce A. King]

Most inspectors agree that the term "double lugging" fits this condition better since it is a lug involved and not a breaker or terminal screw.

[Bruce Thompson]

Originally Posted by tdietrich1

Photo 1:
- Under the same lug, are they different conductor material? Al and Cu?

Photo 2:
- Did you call out improper cable connectors? (cables coming through knockouts)
- Did you actually see a bonding strap/screw on that neutral bar?
- Feeder appears coming through a conduit, is the locking ring properly sized?

tom

I'm glad you asked that b/c I was so wondering about the tap, I didn't look. Fortunately I have other photos that show the sec was copper. Thank you very much for asking!

photo 2:
Yes on the knockouts, but the bonding strap/screw is my question too. I am weak on this. So should the bonding strap be (or not) connecting the buss bar to the enclosure -- is that what is meant for this subpanel rule? Or is it the white neutral and circuit grounding conductors going into the same bar the problem. Obviously there is no where else for them to go, but this subpanel thing is blowing me away. I don't understand it. I've read the NEC stuff and whew... I need plane inglush.

I think that locking ring was just hanging there. It appears there is another smaller one behind it.

Thanks
Bruce

[Bruce Thompson]

I should mention the entire home is not grounded. Actually a few outlets did read that they had a ground but most did not.

[tdietrich1]

Originally Posted by bking

Most inspectors agree that the term "double lugging" fits this condition better

Understood.

When speaking to people, most people understand what 'tapping' off something means. So I use this. I don't want to have to explain what 'lugging' is. Too lazy.

tom

[Paul W. Abernathy]

Originally Posted by bthompson1

Obviously there is no where else for them to go, but this subpanel thing is blowing me away. I don't understand it. I've read the NEC stuff and whew... I need plane inglush.
Thanks
Bruce

Only a phone call away my friend......only a phone call away to anyone in a JAM and needs something explained to them.....

BETTER YET......come over and post all those electrical questions anytime you need at www.theelectricalguru.com as well...We only deal in electrical questions over there...so if you end up with a REAL tough one....visit their also.

[George P. Wells, CMI]

Originally Posted by bthompson1

Obviously there is no where else for them to go, but this subpanel thing is blowing me away. I don't understand it. I've read the NEC stuff and whew... I need plane inglush.

Bruce,

Don't feel bad about not understanding grounding and bonding of panels. I've been teaching apprentices, journeymen, and electrical contractors for many years. You might be surprised to know that even many experienced master electricians and electrical contractors do not understand the rules for and bonding sub-panels. There are some instances where a sub panel can be grounded the same as it would be if it were the main panel on a separately derived system.

The NEC is not a design guide. It is a set of rules. I would not recommend trying to learn from the NEC. There are many good books available but my all time favorite is "Practical Electrical Wiring" by H.P. Richter. I'm not much involved with apprentices anymore so I don't know if it is still being published but, that was always the first book I'd have them read.

The important thing to know is that even though most subpanels are required to have the grounded and grounding conductors isolated from one another, that is not always the case. So, be careful how you report it to your client. Don't list it as being a deficiency unless you are sure. If you are not sure, recommend evaluation by a qualified electrician.

[Bruce Thompson]

Originally Posted by gwells

Bruce,

Don't feel bad about not understanding grounding and bonding of panels. I've been teaching apprentices, journeymen, and electrical contractors for many years. You might be surprised to know that even many experienced master electricians and electrical contractors do not understand the rules for and bonding sub-panels. There are some instances where a sub panel can be grounded the same as it would be if it were the main panel on a separately derived system.

The NEC is not a design guide. It is a set of rules. I would not recommend trying to learn from the NEC. There are many good books available but my all time favorite is "Practical Electrical Wiring" by H.P. Richter. I'm not much involved with apprentices anymore so I don't know if it is still being published but, that was always the first book I'd have them read.

The important thing to know is that even though most subpanels are required to have the grounded and grounding conductors isolated from one another, that is not always the case. So, be careful how you report it to your client. Don't list it as being a deficiency unless you are sure. If you are not sure, recommend evaluation by a qualified electrician.

Thank you for the advice. I'll try to find that book. Also Paul A. has offered some assistance.

Once again, thanks to all you NACHOs

Bruce

[Jim Port]

Along with the missing connectors that someone has already pointed out, it looks like a flexible type cord is being used instead of a listed Class 3 wiring method.