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-   -   Generator installation recommendations (http://www.diychatroom.com/f18/generator-installation-recommendations-145481/)

operagost 05-31-2012 12:38 PM

Generator installation recommendations
 
I already have a Centurion (Generac) 3250W generator with a 20A 240V twist-lock outlet. I would like to hook it into my electrical system so that I don't have to use extension cords and have the option of powering any hard-wired systems. Between an auto-transfer switch, a manual transfer with a sub-panel, and an interlock system, I've chosen the interlock for the following reasons:

1. Least expensive. We have other concerns, and this system will be adequate to safely run our critical systems.
2. Can power any circuit on-demand. Despite the best plans, sometimes you make mistakes and that circuit you really need up isn't on the sub-panel. Also, we have 200A service (Siemens panel) with a 100A subpanel in the addition, and I haven't found a manual-transfer switch that supports a 100A circuit. The 100A panel controls vital circuits like the kitchen and a bathroom.

Does anyone have recommendations for an interlock switch, outdoor inlet (I'm thinking 30A to a new 30A breaker), power monitor to signal when power returns, cords, etc? What's the maximum recommended length of extension cord for this application?

Thanks!

JulieMor 05-31-2012 02:08 PM

Is this you're intended setup?
http://www.interlockkit.com/images/wirediagram03a.jpg
http://www.interlockkit.com/intro2.htm

I can't recommend any specific brand because I've never installed this but the website where I got the image seems to meet your needs.

I would keep the cord as short as possible or upgrade the size. The biggest problem I see is once you have your panel running off the generator there's always the temptation to turn on "just one more" breaker or load.

operagost 05-31-2012 02:45 PM

That's what I intend to do.

The idea is to plan everything we'll need and how we'll start the system, and document that. I'm not planning on just firing up stuff and hoping the breaker on the generator will let me know when it's too much. This includes stuff like oil burners, circulators, pumps, and other stuff that just comes on by itself.

I'm looking for a safe upper end for the extension cord, because I'd like the inlet to be on the front side of the house closest to the panel, but have the option of keeping the generator as far back as possible. We are rural, but we still have odd characters who might be dumb enough to mess with our generator. I'm guess from the fact that 30A twist locks peak at 25' premade might indicate that's a reasonable cutoff point.

wareagle 05-31-2012 02:59 PM

You had better check with your inspector before installation. New code requires the generator to power the whole house load. In your case the 3250 kw could not do this. Also you have specific grounding requirements.

Earnie 05-31-2012 03:01 PM

I'm not an electrician. Just a home owner.

I have a Midwest 200 amp manual transfer switch for my Generac 240 volt, 7500 watt portable generator. One feed is from the power meter and the other is from a NEMA-50 receptical box. If needed, the generator is connected to the receptical and the TS lever is moved to the generator.

I do switch off circuit breakers for all high demand circuits such as the HVAC, dryer, and water heater. The 240v feed allows me to power any circuit on either leg of the panel.

Over the past few days I was asking questions in another forum about using a portable generator with electronic devices. Items such as tv, sat receiver, new refrigerators and clothes washers with electronics. My concern ways the quality of the power supplied by a portable generator. Most agreed that there shouldn't be any issues as long as the generator is not at capacity.

If near capacity and a demand is made on the generator, the voltage supplied could drop to a level which could cause the appliance to switch off.

Also, I'm sure you are aware of start up surges that could easily exceed the output of your 3250 watt generator.

Again, I'm no expert. Just adding my experiences.


A question for an electrician. If the Interlock circuit breaker is on the right side (leg) of the panel, how does it feed the left side (leg)?

JulieMor 05-31-2012 03:10 PM

Typically a 30A load requires #10AWG but distance and insulation have to be factored in. You could buy an 8/4 SO cord (black, red, white, green) and add the cord ends accordingly but will the cord end that matches what's on your generator fit that cord?

Increasing the cord gauge is only a problem when it comes to being able to terminate the cord ends. Before you buy, make sure you can fit the cord to the cord end.

I'd look at this the same as I would a permanent installation and use the appropriate gauge wire for the amperage rating.

operagost 05-31-2012 03:50 PM

Quote:

Originally Posted by wareagle (Post 933169)
You had better check with your inspector before installation. New code requires the generator to power the whole house load.

PA uses IBC 2009, which I understand includes NEC 2008. Article 702 (optional standby equipment) says:
Quote:

1) Manual Transfer Equipment. Where manual transfer
equipment is used, an optional standby system shall have
adequate capacity and rating for the supply of all equipment
intended to be operated at one time. The user of the
optional standby system shall be permitted to select the
load connected to the system.
It's an automatic transfer switch that requires the full load be supported.
I guess the worst that could happen is the inspector could ask me what I plan to run on it. :confused1: I'll already have that planned and typed up in a binder that we keep near the panel. Can you tell I'm an IT guy who specializes in business recovery?

It's 3750 startup load, by the way.

brric 05-31-2012 03:59 PM

Quote:

Originally Posted by wareagle (Post 933169)
You had better check with your inspector before installation. New code requires the generator to power the whole house load. In your case the 3250 kw could not do this. Also you have specific grounding requirements.

That is not true for portable stand-by generators.

JulieMor 06-01-2012 07:52 AM

Quote:

Originally Posted by operagost (Post 933212)
PA uses IBC 2009, which I understand includes NEC 2008. Article 702 (optional standby equipment) says:
It's an automatic transfer switch that requires the full load be supported.
I guess the worst that could happen is the inspector could ask me what I plan to run on it. :confused1: I'll already have that planned and typed up in a binder that we keep near the panel.

Local codes may require a permit and inspection for the installation of the outlet installed on the outside of the house and the hardware installed on the panel. That's your call. Just make sure all the permanent stuff is properly grounded. If you have a 3-wire plug on the generator (hot-hot-neutral) you should make sure you have some sort of ground to connect the outlet box to the case of the generator.

AandPDan 06-01-2012 01:29 PM

An approved interlock is probably your cheapest and best option.

Siemens makes there own interlocks and you can usually find them for MUCH less than the other brand...

Check this link for application data. You'll probably have to order it from a supply house or online.

http://www.sea.siemens.com/us/intern..._Cut_Sheet.pdf

Good luck.

operagost 06-01-2012 02:34 PM

EXCELLENT... I was hoping for one from Siemens rather than the generic. Thanks!

operagost 06-05-2012 10:56 AM

I found which kit I need, which is the same as this guy used:

http://kesterhouse.com/mechanical/wiring.html

But I'm confused. He claims he had to leave two sockets vacant next to the two he's using for his backfeed because "those lugs in the panel would share power with the input breaker." He also claims the kit makes it impossible to use those somehow, which I don't see because they're clearly out of the way of the interlock mechanism. Does this makes sense to anyone? I read the Siemens docs and didn't find any reference to that. My panel is very full, so I absolutely cannot use this if that is the case. I might as well replace the whole thing with one that's designed with generators in mind.

AandPDan 06-05-2012 11:55 AM

What model interlock is it?

I don't see what he's talking about either. The breakers are all on the same buss so ALL the breakers can be energized via either the main or standby breaker.

Not sure on blocking off the breakers, I don't see any issues. Maybe a call to Siemens is in order.

operagost 06-05-2012 01:03 PM

Should be ECSBPK03. I have the G2040MB1200, which according to Siemens requires this model and only this model.

AandPDan 06-05-2012 01:44 PM

I just checked and found some reviews on this interlock. Several of them do indicate that it does block the adjacent breakers.

Check here:

http://www.amazon.com/Siemens-ECSBPK...DateDescending


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