To bond or not to bond neutral and ground in new electric service panel?

[MossRoad]

Loose neutrals can be a real problem. If it is from the transformer to your house, you can get unbalanced voltages. The 110 leg that has the most load will go lower and the other voltage will rise. Burns out all types of stuff in the house. Ballasts, garage door opener transformers, microwaves, etc...

Friends of ours came home one night to see all their outside lights on REALLY BRIGHT!!! Went inside and smelled smoke. Turns out Billybob the drunken neighbor was too drunk to drive, so he had his 8 year old son back his pickup into the driveway. It caught a guy wire on the pole that had the transformer on it, bent the pole into some trees, touched a few wires together, and WOW were those lights bright.

They lost several electronic appliances, both garage door openers, and had to have some circuits re-wired.

And as I recall, Billybob did the exact same thing again within a year.

 

[3Ts]

I had to remedy something that made the chrome-plated kitchen percolator tingle when touched. That could have been deadly if someone added a longer cord and filled it at the faucet while plugged in. I suspect electricity bleeding to ground somewhere was the cause of major pipe corrosion, galvanic action, that seems to have ended after I got a few things wired like they should be.

I had a similar situation. Turned out that when an electrical outlet was installed, the ground wire on the outlet was cut at an angle leaving a really sharp point. Then when it was pushed into the box, the ground wire pierced the neutral wire insulation.

 

[grsthegreat]

Friends of ours came home one night to see all their outside lights on REALLY BRIGHT!!! Went inside and smelled smoke. Turns out Billybob the drunken neighbor was too drunk to drive, so he had his 8 year old son back his pickup into the driveway. It caught a guy wire on the pole that had the transformer on it, bent the pole into some trees, touched a few wires together, and WOW were those lights bright.

They lost several electronic appliances, both garage door openers, and had to have some circuits re-wired.

And as I recall, Billybob did the exact same thing again within a year.

that happens when you break the neutral wire. if the house is wired in what we call an edison circuit (ie two separate circuits utilizing a common neutral) you get 240 between these circuits when you lose the neutral. i personally never share neutrals when i wires houses, but many people do.

 

[Tractor Seabee]

that happens when you break the neutral wire. if the house is wired in what we call an edison circuit (ie two separate circuits utilizing a common neutral) you get 240 between these circuits when you lose the neutral. i personally never share neutrals when i wires houses, but many people do.

Shared neutrals can be real fun when a 2 or 3 pole breaker isn't used when trouble shooting, till you figure it out. Yes, way back on commercial work a shared neutral was allowed on 3 phase. Tied handle breakers were also not required. I believe the current code requires separate neutrals on all circuits. When computers started to proliferate in the working world those shared neutrals ruined a lot of computers. We then started specifying separate neutrals even though code allowed. Shortly it became a trade practice.

Ron

 

[California]

How does shared neutral work - and the alternative - ?

 

[JerryK]

How does shared neutral work - and the alternative - ?

Shared neutral was used a lot in large office three phase lighting circuits. They would run 5 wires out to the area being lit... Green [ ground], White [ common neutral ], Red, Black, Blue [da three phases]. When the lights are turned on the current going thru the lights basically just bounces around between the three phases and little or no current passes thru the white wire going back to the panel. [ the little electrons flowing from negative to positive to fill the holes that are kind of going from positive to negative flow from one phase as it is ebbing into the next phase that is rising, etc ....... ]

 

[crash325]

Look in your power supply, you will see 3 wires going into metal conduit. When they come out only 3 wires are used. No other grounding is needed. That is how the power company supplies your power.

 

[JerryK]

A lot of houses are burned down due to neutral problems. Inadvertent or haphazard neutral wiring... For each X amp breaker or fuse there should be a corresponding correctly sized HOT and NEUTRAL wire going from the breaker/fuse to the load and back. I've run into a few houses that 'someone' lost track of what was what in overcrowded boxes, and started using whatever white wire for whatever, bonding white wires together because they were ' all white ' for some reason, or just using a white wire for a new circuit because it was already there and going back to the main panel anyway.... What usually happens is that you have two or more black wires leaving the main panel off the same phase, each protected by their own X size fuse, and the path back from the load is just one white wire. Code is written so that the conductors [ wires ] in a home do not heat up and cause fires, so the X fuse should not heat the black wires leaving the panel. But since the white wire now carries twice as much current than the code allows it will heat up. I've opened up ceiling boxes where the white wires were almost too hot to touch. Most of the problems turned up to be white wire related....

 

[California]

Ah-ha! I have a circuit like that.

Its a 12/3 run from the barn panel to a barn stall that was remodeled (before me!) for washer and gas dryer on one leg (black) of the 12/3 and then across the room, a refrigerator on the other side (red) of the same 12/3.

That refrigerator is no longer run from that circuit, I moved it elsewhere then plugged it into the 12/2 lighting circuit - where I have to unplug it (and turn off several 150 watt lights) if I run the compressor over in an adjacent stall.

Like I posted before, Dad said just bulldoze this place after he was gone, it's cute but it's beyond help. Now I'm quoting that to my kids.

 

[rhunt]

There is value in hiring an licensed electrical contractor and taking out permits, and having final inspections. Just my two cents. Bob