Grounds and Neutrals bonded improperly affect Low Voltage Lights?

[MisterMoSparky]

Main Disconnect outside G-N bonded, 4-wire going into main panel, Main Panel has G-N bonded also. My customer called me out there to fix their landscape lights and one of their 600W Transformers had burned out. I recommended having their grounds and neutrals separated in the main panel. During a surge event, the over voltage that’s traveling along the ground and neutral bar in the main panel to eventually make it to the ground rod outside will slightly effect the low voltage electronics and lighting around the house over time. Is my thought process wrong?

 

[jaggedben]

I doubt the N-G bond in the panel had anything to do with the transformer issue, but it is still correct once you are past the service disconnect N and G must be kept separate.

 

[MisterMoSparky]

I doubt the N-G bond in the panel had anything to do with the transformer issue, but it is still correct once you are past the service disconnect N and G must be kept separate.

I agree it didn’t break the transformer.
I offered to replace the transformer to fix the lights. But as a recommendation to help prevent it along with the lights being damaged over time, (huge home with at least 25 low voltage circuits coming into 4 different transformers) I recommended putting a surge protector on their outside disconnect and having their G-N separated in their inside panel.

 

[infinity]

Main Disconnect outside G-N bonded, 4-wire going into main panel, Main Panel has G-N bonded also. My customer called me out there to fix their landscape lights and one of their 600W Transformers had burned out. I recommended having their grounds and neutrals separated in the main panel.

Yes the bonded neutral in the panel needs to be unbonded. Just out of curiosity where do the GEC's terminate?

 

[MisterMoSparky]

Yes the bonded neutral in the panel needs to be unbonded. Just out of curiosity where do the GEC's terminate?

The GEC lands outside in the first disconnect. I know that the only place for the N-G bond should be at the first disconnect only. My customer has been getting other electricians from his place of work telling him that, yes the N-G bond shouldn’t be in the main panel but it has no effect whatsoever on the low voltage lights. From how a Surge Protector works utilizing a good Ground Electrode to send over voltage away from equipment and electronics, it only makes sense that if there was a surge event raising the voltage in the lights outside that it should have a direct path back to the GEC instead of equally traveling along the neutrals in the improperly bonded main panel. I just want to know if my thought process is valid or not?

 

[infinity]

My customer has been getting other electricians from his place of work telling him that, yes the N-G bond shouldn’t be in the main panel but it has no effect whatsoever on the low voltage lights.

I agree. The bonded neutral in the panel is just sending some of the neutral current back to the service disconnect on the EGC which wouldn't affect the low voltage lights.

 

[MisterMoSparky]

I agree. The bonded neutral in the panel is just sending some of the neutral current back to the service disconnect on the EGC which wouldn't affect the low voltage lights.

Okay got it. What exactly are the effects of double bonded G-N then? I know that it causes parallel Neutral paths like you just said but how exactly does this effect a homeowner?

 

[jaggedben]

...From how a Surge Protector works utilizing a good Ground Electrode to send over voltage away from equipment and electronics, it only makes sense that if there was a surge event raising the voltage in the lights outside that it should have a direct path back to the GEC instead of equally traveling along the neutrals in the improperly bonded main panel. I just want to know if my thought process is valid or not?

Not valid.

If the surge is from the utility voltage, then ground is pretty irrelevant; the voltage wants to return to its source, not the ground. The surge protector works by very quickly becoming a load that drops the voltage (hopefull) back down to where it doesn't damage items connected in parallel.

If the surge is from lightning, the possibilities are much more random and luck of the draw. The paralleled EGC and neutral might encourage charge to travel over the neutral which would be less desirable than traveling over the EGC. However by your logic of needing a path back to ground, the parallel paths would be better not worse. But theoretically it all depends where the charge makes it's way onto the wiring.

The reasons for keeping neutral and EGC separate have to so with reducing shock potential from normal voltage where there's a fault, and nothing much to do with surges.