Thread: Bond Screws

..........

Similar Threads:

• Neutral bond at Siemens panel
• Bond Tester opinions requested
• bond/ground at gas regulator
• Stranded conductor split under two terminal screws?
• Rust on bus bar, breaker screws

Those green bonding screws do need to be removed. Plus, neutrals and grounds have not been separated.

Originally Posted by John Arnold

Those green bonding screws do need to be removed.

ONE does. The other does not.

Plus, neutrals and grounds have not been separated.

Yes, remove that metal cross over bar at the bottom and replace it with a plastic one made for that purpose (DO NOT remove the metal one and not replace it with the plastic one).

The grounding terminal bar with the bare wires, that bond screw can stay.

The neutral terminal bar with the neutrals wires, that one needs to be removed along with the cross over bar.

Yes, of course, Jerry is right. I wrote before I thought it out completely. I think I feel a fever coming on.

Neutral has to be separate from ground on the left picture. Can't run neutrals to a ground bus bar in a sub-panel.

In the second photo the bond screw should come out on the neutral side for a free floating neutral back to the main disconnect.

ref: NEC 250.142b

Good catch.

Commentary NEC 250.142b - When neutrals and grounds are bonded (connected) together, the return neutral current will split (not necessarily equally) and run on parallel paths through the grounding and neutral system back to the main panel and up the neutral to the transformer. This parallel travel can cause unbalanced conditions in the system because the current remaining in the neutral will not counterbalance the current in the hot wire. The resulting imbalance creates a magnetic field that can interfere with sensitive electronic equipment, especially audio and video equipment. In a metal conduit system, the imbalance will induce current into the conduit, which could cause the conduit to overheat. In some cases, neutral current travel on the grounding system and other metal systems, such as piping or ductwork, can be a shock hazard.

Originally Posted by dan orourke

Why can the bond screw stay in the first picture (exterior panel) and not in the second (the garage located panel)?

Because I thought they were the same panel and you were showing both sides of it.

The first photo has bare grounds in it, which I referred to, so that would be the grounding side, which I referred to.

HOWEVER ...

I had to go back and look to answer this last post of yours and I now see some white wires above the bare wires. (Guess I'm still not all here.)

Being as the service equipment is ... some place else ... (does not matter where) ... the neutrals and grounds are not allowed to be bonded at this panel, which means that one side needs to be made into the ground terminal bar and the other side made into the neutral terminal bar as I described previously, OR, move the grounds to a separate ground terminal bar. Doing the latter would make this side into a neutral terminal bar too - in which case we are now back to John's answer - remove both screws.

So, the answer is, "it depends" on the choice you make.

Those answers apply to both panels equally.

Isolate the neutrals from the grounds, isolate the neutral from the enclosure, bond the ground to the enclosure ... when not at the service equipment.

John, right? Or am I seeing double here.

Originally Posted by dan orourke

do these bond screws that are in place actually bond the bus bar to the panels...?

Look at the schematic in the panel or on the back of the door. It will tell you exactly which screw in the busbar is for bonding (should be green, of course).

Dan,

That's how NOT to but a wire which is too small for a terminal into that terminal.

There is no 'correct way' to put a wire which is too small for a terminal into that terminal.

BUT ... ... if that terminal IS rated for that size wire, then that IS STILL the wrong way to put it in there. Just increases the potential for things to come loose.

The schematic Neal referred to, or some other listing (sometimes in table form) will state what size wires those terminals are rated for, and it will state the torque required for proper tightening - as though the electrician actually carries that torque wrench with him like he should.