Why is it considered unsafe to double post neutral wires (two neutral wires to one lug on the neutral bar) in an electric panel?

biggsie

This is unsafe due to the need to turn off multiple circuit

breakers to work on any of the circuits using these wires.

If a person is working on one circuit and turns off a breaker

it is possible that the second neutral is carrying current and

is a shock hazzard when removed from neutral buss

tkrussell

Simply because the lug is only rated to handle one wire safely. Any more than rated will result in loose connections.

Stratmando

Its a code violation also, The code is based on safety, Not necessarily efficiency.
I forget the exact wording in a paragraph at the start of the Electrical Code, that states just that.

Cobraguy

Biggsie...I don't believe this has anything to do with that scenario does it? Since the neutrals are all on the same buss anyway, that problem is always present. The only way to ensure your problem doesn't occur is to have the MWC on tied breakers. Or am I misunderstanding what you're saying?

Stratmando

Hey Cobra, I'm thinking he meant 4 breakers would need to be turned off to safely work on a neutral problem, if 2 neutrals under one screw. Provided they were all multi circuit.
Take Care.

RustyFairmount

What biggsie said makes sense to me. Here's the scenario:

Assume every breaker in your panel is on, and all circuits are under load. You turn off one breaker and attempt to remove it's corresponding white from the neutral buss. In the process, the second white pops out and makes contact with you. ZAP!

This is an excellent question. I don't believe in following code just because it says so. It's always wise to question code so that you can learn the reason why it is that way, and then follow it! Understanding why code exists is always a good thing.

Stratmando

Another reason is if neutral is removed on a multi circuit while energized, the 120 Volt circuits using that neutral may go to 240 volts if load or breaker(s) are not turned off.

labman

It may be a bad practice, but come on, who is going to shut off one circuit and loosen 2 wires?

Stratmando

If I was redoing a neutral connection that was overheated due to loose connection, I would turn off 2 circuits to repair. If 2 neutrals under same screw. 4 circuits need to be turned off.