Bonding of Service Panel

[Kenny Rigler]

Hey Guys-

This home had an overhead service to the meter then directly into the home via the attic to the service panel. No service disconnect on the exterior. Since this is the panel with the main disconnect, shouldn't the neutral and ground bus bars be bonded?

The meter had a grounding electrode and it appears that they ran a grounding conductor off the ground bus bar below somewhere...possibly to the copper water lines in the crawlspace, but I was not able to locate it.

Thoughts?

Thanks...Kenny.

[Jim Port]

You appear to have a couple of issues. The lack of the bond screw, improper fitting used to connect NM cables to the panel and the length of unfused cable inside the attic.

Unfused SE conductors are required to be "as short as practical". From the description it does not sound like this install would meet that requirement. If the unfused conductors cannot meet the above then a disconnect is installed to provide overcurrent protection and then the cable length does not matter. However, this would now require a 4 wire feeder from the disconnect to the panel where the grounds would be isolated from the neutrals.

[Buck Hartley, CMI]

Kenny,

What is the BRAND name of this panel?

[Kenny Rigler]

Originally Posted by bhartley

Kenny,

What is the BRAND name of this panel?

Buck, it's a Square D.

[Jim Port]

This this is the QO Square D line.

[Buck Hartley, CMI]

Kenny,

The only reason I ask about the BRAND is that I only saw Square D breakers in lower part of the panel. Thought maybee it was a different panel. Refer the panel to a qualified electrician, when in doubt

[Kenny Rigler]

Originally Posted by Jim Port

You appear to have a couple of issues. The lack of the bond screw, improper fitting used to connect NM cables to the panel and the length of unfused cable inside the attic.

Unfused SE conductors are required to be "as short as practical". From the description it does not sound like this install would meet that requirement. If the unfused conductors cannot meet the above then a disconnect is installed to provide overcurrent protection and then the cable length does not matter. However, this would now require a 4 wire feeder from the disconnect to the panel where the grounds would be isolated from the neutrals.

Thanks Jim. What problem does the lack of a bonding screw create in this situation...for my educational purposes. In reference to the SE conductor, what does unfused refer to?

Kenny

[Jim Port]

Unfused cable is without any overcurrent protection installed. An example would be between the meter and the panel. Once overcurrent protection is installed the length of cable inside is not regulated by the NEC. Overcurrent protection can be a breakered disconnect either immediately inside or on the outside of the house.

Without the bond screw a live conductor could short to the enclosure without tripping the breaker as there would be no fault path. This could also create a shock hazard to anyone that touched the panel.

[Michael Larson]

There appears to be a bond screw immediately below the neutral of the SE.

[Robert Meier]

There are several issues with the service raceway. For one, judging from the photo and depending on the jurisdiction, it may be too long to be inside of the dwelling. [230.70(A)(1)] The service raceway must be bonded on one end with something other than standard lockmuts, since we can't see into the meter neclosure it may or may not be propoerly bonded. Even though there may be no bonding jumper within the panel from the neutral to the cabinet, the cabinet would be bonded by virtue of it's connection to the service raceway.

[Jim Port]

Originally Posted by mlarson

There appears to be a bond screw immediately below the neutral of the SE.

Going to differ with you Michael,

I think that is a screw to hold the neutral bar to the bracket. Also the Square D bond screws are a green color.

[Paul W. Abernathy]

Originally Posted by Jim Port

Once overcurrent protection is installed the length of cable inside is not regulated by the NEC. Overcurrent protection can be a breakered disconnect either immediately inside or on the outside of the house

Please explain.....You lost me on that one. Are you saying the cable between the meter and the panel OCPD is not regulated by the NEC....or the cable inside on the load side of the OCPD is not regulated by the NEC. Im confused because both are regulated by the NEC.

Please clarify fella......

[Paul W. Abernathy]

I agree with Jim....their is no bonding screw in this panel. It would usually be upper right and it would indeed be green.

[Jim Port]

I do not think that panel is feed with a raceway; the neutral is braided like SE cable, not insulated, and that looks like a PVC terminal adapter in the panel.

I don't see how anyone can make a determination on the length of the SE conductors based on those pics.

[Jim Port]

Originally Posted by Robert Meier

There are several issues with the service raceway. For one, judging from the photo and depending on the jurisdiction, it may be too long to be inside of the dwelling. [230.70(A)(1)] The service raceway must be bonded on one end with something other than standard lockmuts, since we can't see into the meter neclosure it may or may not be propoerly bonded. Even though there may be no bonding jumper within the panel from the neutral to the cabinet, the cabinet would be bonded by virtue of it's connection to the service raceway.

Robert, are you using 250.97 regarding the raceway bond? If not what Article are you using?