Originally Posted By: psmothers This post was automatically imported from our archived forum.
I have been seeing quite a few newer panels in the last month or two that all look great except that the have double lugged neutrals. It has always been my understanding that each neutral should have its own lug/set screw. What is the code reference to this and exactly what are the problems with doubled lugged neutrals from a technical stand point?
-- Foxe Smothers
"Its not a matter of will we rebuilt it is matter of how soon..."
"A hero is no braver than an ordinary man, but he is brave five minutes longer."
- Ralph Waldo Emerson
I have a technical question for you and since you are an electrician this should be realitively easy for you.
You had stated that only one neutral per termination. Grounds can be terminated per manufacturer's specs. I agree, that is what the good book states.
Since you are not allowed to place two neutrals under one termination, is it ok to place one neutral and one ground under the same termination? (same wires from the same circuit, or seperate wires from different circuits) Please explain your answer.
Joe Myers
Joe,
My answer would be no because a neutral is a current carrying conductor where a ground is not. Also the neutral bus bar is not rated for double lugging. Typically the largest gauge wire you can put into a neutral buss is 4 gauge and it fits quite tightly. Regardless of that fact though, I do not ever double lug any wires other than a ground and a ground purely because grounds are not current carrying conductors. Double tapping and lugging can create hot spots on breakers and neutral bars if not tightened to the correct torque and especially if two different size conductors are used. This is especially true if aluminum conductors are used and they are not protected against corrosion with De-ox. Because the hot and neutral wires are current carrying conductors, the chance is then greater for potential hot spots. If the double tap or lug becomes lose, it begins to arc. As it arcs it builds up carbon. Carbon is then resistance and with the more carbon buildup the more difficult it is for the conductor to make contact....thus increasing the current. End result can be the breaker tripping because of the loose conection (excessive current exceeding the rating of the breaker), or signs of overheating such as discolored wires, melted wires, etc, or worse yet...fire! I have often double lugged ground wires and have yet to fail a EI inspection for it. You will never see a panel done by me though that has double tapped hots or double lugged neutrals. I just won't do it....to me it is a safety issue.
-- "I have never met a man so ignorant that I couldn't learn something from him."
Galileo Galilei
Originally Posted By: dvalley This post was automatically imported from our archived forum.
Peter,
Good info there.
Call it out, no matter what.
I've done plenty of brand new installations and recent Amperage upgrades that have had numerous double lugging of neutrals. I call every one of them out for an Electrician to evaluate and correct.
I would say about half of my inspections (believe it or not) get an Electrical report that states "Double lugged neutrals".