Common trip vs common disconnect

[brother]

The issue of common trip vs common disconnect has come up again. Apparently some local areas are thinking of requiring the water heaters and all other line to line voltage loads be required to have a 'common' trip' for any conductors supplying the same equipment. I use to think that it was already required for water heaters, but learned that was not the case some time back. The reason for the change aparrently there was another incident they claimed contributed to a shock when the other poles of a breaker did not trip off even though it had a handle tie. This was feeding the same equipment.

What do you think, should this also be a new NEC requirement?

 

[winnie]

The NEC is about practical safeguarding. To my mind 'practical' boils down to cost versus benefit.

Is the issue someone approaching a water heater that is off but still energized because of single pole tripping, and they didn't bother to cycle the breaker to off?

For breakers there is minimal cost to requiring common trip. What is the actual cost difference of two (or 3) single pole breakers connected using a handle tie, versus a single multi pole common trip breaker? IMHO about the only cost would be the inability to use existing spare single pole breakers.

If the only issue were breakers I'd be for this suggested change; small benefit (protecting people who don't follow proper precautions) but also very small cost and thus worth it.

Are single pole controls ever used for water heaters? This might be a bigger cost issue, and I don't see the benefit being worth the cost here.

Jon

 

[Tulsa Electrician]

Hope they tink this thru before making it a requirement.

 

[Tulsa Electrician]

Wanted to add.

They should read 422 part 3 before making a new rule. I would bet in Every case they failed to open the handle to off position and then failed to test with a working tester.
If replacing the tank most likely did not install a bonding jumper between hot and cold when it has metal lines.

Training and common sense goes a long way.

How would a common trip fix bonding around the metal pipe if there was voltage present on the metal line or improper GEC connection etc.

Now we can see why a additional electrode is required if the water line is used as an electrode.

On a lot of old houses the wire was ran to the tank instead of at point of entry.

With an electric water tank the EGC of the branch circuit serves or can as the bonding requirement which there unhooking to replace.

Also breaker fail, so what's next after common trip for branch circuit.

Then what do they do when it has more than one branch circuit.

Just some thoughts

 

[NTesla76]

Very rarely, around here, do I see a bonding jumper between water lines on a water heater.