# Transfer switch



## sparky723 (Jul 22, 2008)

Have a customer thinking of installing a transfer switch for a 4k watt generator...

It is, of course, a portable generator that will be hooked up and set under a carport which in fact is directly opposite the main panel.

Does anyone have a preference or choice of a transfer switch that would fit this application best?

Thanks.


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## erics37 (May 7, 2009)

A 4 kW isn't going to give them a lot of power, might be easier and cheaper to backfeed a breaker on the panel and install an interlock kit.

Alternatively, they make panels with transfer mechanisms all installed and ready to go, too.


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## sparky723 (Jul 22, 2008)

erics37 said:


> A 4 kW isn't going to give them a lot of power, might be easier and cheaper to backfeed a breaker on the panel and install an interlock kit.
> 
> Alternatively, they make panels with transfer mechanisms all installed and ready to go, too.


Gonna plead dumb...
I've never done either of these methods. Can you explain them like I'm a third grader?:laughing:


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## erics37 (May 7, 2009)

sparky723 said:


> Gonna plead dumb...
> I've never done either of these methods. Can you explain them like I'm a third grader?:laughing:


An interlock kit allows you to backfeed a circuit breaker from the generator.... it is a mechanical device that physically prevents your backfed generator breaker from being electrically closed at the same time as your panel's main breaker. The issue is, during an outage, if you have your generator running and your main breaker is still on, you could be backfeeding the power company transformer and thus energizing power lines that aren't supposed to be energized, putting linemen at risk.

There are a zillion kinds of interlock kits, you would want to get the one specifically for your make & model of panel. Visit interlockkit.com, they should have all the different ones there.

Functionally, here is how the kit works:










So basically, power goes out. Homeowner goes and shuts off the main breaker and all the branch circuit breakers, plugs in their generator, fires it up, then turns on the backfed circuit breaker, thus energizing the panel bus from the generator. Then they will have to pick and choose which circuit(s) they want on. They won't be able to get much with a 4 kW generator but it'll keep the fridge going and some lights on and other stuff.


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## sparky723 (Jul 22, 2008)

erics37 said:


> An interlock kit allows you to backfeed a circuit breaker from the generator.... it is a mechanical device that physically prevents your backfed generator breaker from being electrically closed at the same time as your panel's main breaker. The issue is, during an outage, if you have your generator running and your main breaker is still on, you could be backfeeding the power company transformer and thus energizing power lines that aren't supposed to be energized, putting linemen at risk.
> 
> There are a zillion kinds of interlock kits, you would want to get the one specifically for your make & model of panel. Visit interlockkit.com, they should have all the different ones there.
> 
> ...


The main panel is already installed and everything is terminated. It's a 200A CH.
Will that interlock kit work? If so, how's it different from a manual transfer switch?
The 4k gen. Should get them about 4-5 circuits. 
I'm thinking their h.w. heater and some lights and convienence plugs.


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## erics37 (May 7, 2009)

sparky723 said:


> The main panel is already installed and everything is terminated. It's a 200A CH.
> Will that interlock kit work? If so, how's it different from a manual transfer switch?
> The 4k gen. Should get them about 4-5 circuits.
> I'm thinking their h.w. heater and some lights and convienence plugs.


If the generator is portable then you just need to get the appropriate sized cable and generator inlet, then run the appropriately sized circuit conductors back to the panel. Rearrange the existing circuits to make a couple spaces available on the upper right. Pop your generator breaker in there, follow the interlock kit instructions, wire the generator circuit to the breaker, and you're done. No transfer switch necessary.


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## Bbsound (Dec 16, 2011)

Good luck with that water heater. They are usually 4500 watts.


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