Interlock vs. throwing the main circuit breaker for generator powering a house

[ultrarunner]

User Error cannot be underestimated...

Ever hook up Jumper Cables reversed or tried to start a car and the engine was already running?

A good system has fail safe.

 

[Oldoak]

An interlock is an acceptable alternative to a transfer switch in some areas. Stating an interlock is the safest device is not valid. A transfer switch is a complete, positive disconnect from the power grid.

Why a Generator Needs a Transfer Switch

As was stated in a prior post, an interlock is the safest between the two options the O.P. was inquiring about.

 

[TheMan419]

Cannot imagine installing a generator that is just back fed. We went w the sub panel. It has two switches that cannot both be on at the same time.

Wife thought this made the most sense to her for operating if I were not home. Same reason generator has electric start.

 

[LouNY]

A legitamate transfer switch interrupts the neutral bond to the electrical grid. Opening a circuit breaker does not. That is a huge safety concern for utility personnel and a major reason that most codes require a transfer switch.

I haven't installed a new transfer switch in 20 years or so,
at that time they were double throw 2 pole devices, the
neutral was not switched or disconnected and they where done to code.

 

[marchanna]

Funny we’re talking about this. My power just went out and I had to fire up the generator. I don’t have a lot of gas, so no non-essentials. Fortunately, we’re having a heat wave relatively speaking, so I probably don’t have to burn wood for heat.

 

[RickB]

I haven't installed a new transfer switch in 20 years or so,
at that time they were double throw 2 pole devices, the
neutral was not switched or disconnected and they where done to code.

The one I had installed in NY was a three pole double pole switch and the neutral was switched to the generator feed.

 

[MossRoad]

Anyone have a link to the code that shows the neutral should be switched?

 

[RickB]

Anyone have a link to the code that shows the neutral should be switched?

I do not. The few transfer switches I have stuck my head inside all did disconnect the grid neutral. I do not know electrical code and have avoided claiming that I do.

 

[kenmac]

I have a 400 amp service to the house. My shop 200 ft from the house is fed from one of the 200 amp breaker boxes at the house. Interlock wouldn't work in my application. I have to turn off both breakers and some of the other 220 breakers.
The power company here assumes people will have generators connected, so they work an outage with that in mind

 

[aczlan]

I do not. The few transfer switches I have stuck my head inside all did disconnect the grid neutral. I do not know electrical code and have avoided claiming that I do.

IIRC, IF you switch the neutral, it has to be bonded to ground in the generator and upstream of the transfer switch. If you do NOT switch neutral, you CANNOT have the ground and neutral bonded at the generator.

Aaron Z