Originally Posted By: bking
This post was automatically imported from our archived forum.
There are many different panels and wiring styles therefore a picture will not always provide you with the necessary knowledge. Make sure you understand all of the following and then if someone posts some pictures, study those and reread the following. I will look for some pictures and try to post.
This info is for all panels that are not service equipment panels:
Service equipment panel is where the first point of disconnect is.
You have to recognize the neutral feed and its termination point.
This bus bar should have only white wires on it but sometimes other colors may be there and it could be still isolated from ground. If bare copper wires are on the neutral bus it is not correct. Look for splices in the panel where a bare copper may be spliced to a white wire and then terminated on the neutral bus.
The neutral bus bar has to be very closely examined to see if any bonding screw is passing through to the panel box. Many times when it is done correctly you will see a threaded hole behind the bus bar that has no screw. If you see a green screw in the neutral bar you can be pretty sure it is wrong. Sometimes you will find a neutral bus bonding strap that goes across the panel and sometimes under some black plastic. Look for anywhere a hidden bar or strap may be and look for screws or bolts that are connecting it.
Also examine the ground bus and look for any white wires on it.
make sure the ground bus does have a screw (green preferred) into the panel box or a small copper strap bolted from the bus to the box.
If you see only a three wire feed to the subpanel, and you are sure it is a subpanel, and the panel serves 3-wire outlets with ground wires then you most likely have an improperly wired panel. To have a floating neutral you need 4-wire feed unless the 3-wire feed uses a metal conduit for the ground. Then you have to make sure the neutral is not bare and touching the panel box.
How was that, I did not even copy and paste code..... ![icon_biggrin.gif](upload://iKNGSw3qcRIEmXySa8gItY6Gczg.gif)