Portable gen arrived today. Now I need to decide which method to wire to panel - standalone transfer kit vs. interlock direct to panel ... I will be hiring this out either way. For those who already made this jump, which way did you go & why? Is either option head and shoulders above the other?

Also trying to decide on this. But man, I think we need a Generator Board right now

Had transfer switch installed with the generator 16 years ago. Works great! Lasts long time!

What generator? Fuel source?

I'm not an electrician but spent 17 years doing disaster recovery which included a lot of standby and portable power sources.

Here's my $0.02...

If your genset will be connected all the time, go with ATS and wire it to auto start the genset.

If you are going with hookup as needed, you can go with manual transfer switch or interlock. In my opinion, transfer switch is better if you are going to be over about 50 amps. Under that, might as well use an interlock.

The other advantage to the interlock is you can easily install it yourself and don't have to cut utility power to do so. You can install a transfer switch yourself, if you have the know how, but need to disconnect utility power so you can move the mains. Its best to have the utility company disconnect it. They get *****y if they find out you pulled their meter.

I'm looking at Westinghouse 9500DF with the following specs. I imagine you'd recommend a transfer switch instead of an Interlock? Why is it a better option?

The idea of the interlock seems nifty to me. if you had a 10 circuit transfer switch you would obviously only have those 10 circuits whereas with the interlock you can run any circuits you want as long as you don't overload the generator. That seems nice to me plus they are cheaper

Bottlerocket said:

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The idea of the interlock seems nifty to me. if you had a 10 circuit transfer switch you would obviously only have those 10 circuits whereas with the interlock you can run any circuits you want as long as you don't overload the generator. That seems nice to me plus they are cheaper

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That's exactly why I think I'd prefer going with Interlock. Unless I'm just really missing something, it seems a transfer switch simply serves to "dumb it down" so you don't over load your generator. Seems like as long as you are paying attention to what breakers you turn back on after swapping power sources you'll be ok.

skelso said:

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I'm not an electrician but spent 17 years doing disaster recovery which included a lot of standby and portable power sources.

Here's my $0.02...

If your genset will be connected all the time, go with ATS and wire it to auto start the genset.

If you are going with hookup as needed, you can go with manual transfer switch or interlock. In my opinion, transfer switch is better if you are going to be over about 50 amps. Under that, might as well use an interlock.

The other advantage to the interlock is you can easily install it yourself and don't have to cut utility power to do so. You can install a transfer switch yourself, if you have the know how, but need to disconnect utility power so you can move the mains. Its best to have the utility company disconnect it. They get *****y if they find out you pulled their meter.

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Blue parachute for you.

The reason I say transfer switch over about 50 amps is due to several things. Including availability of breakers over 50a, room needed for the breaker, etc. In some boxes, there is no issue, in others there is so you have to weigh the options for your specific situation.

I should also be clear that when I speak of transfer switch, I mean just that. The mechanical means to swap power sources. I am not talking about the sub panels that include a transfer mechanism. Nothing wrong with those but I prefer to energize the entire panel and shut off un-needed circuits.

In the end, it comes down to personal preference unless you are going with an auto transfer switch.

I didnt pull the details on the genset you listed. Make sure you can get full load on one circuit.

An example of what I mean when I talk about transfer switch: https://www.auberins.com/index.php?main_page=index&cPath=1

skelso said:

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The mechanical means to swap power sources. I am not talking about the sub panels that include a transfer mechanism. Nothing wrong with those but I prefer to energize the entire panel and shut off un-needed circuits.

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Sounds like you are talking about an interlock.

So, while i might be able to install the actual interlock switch on the panel myself, looks like I still need a professional to install the plug-in outlet and wire that to the two panel circuits that are allowed to switch to generator power when the interlock is engaged . It's not simply the interlock device itself. Do I have that right?

My last house had a 7,000 dollar Zenith Controls automatic transfer switch that took up more space than all of my breaker panels combined. It had a lot of fancy LED and indicators to te you when the power was off. Lol. Then they dropped a 30kw diesel generator behind it .... that had to be manually started. It seemed goofy. When I moved, I left the panel and took the generator with me.

I'm going with the interlock all day long regardless of size. I regularly install and move panels at my place because I'm comfortable with it. I don't like "automatic" anything. I want to be completely in control of when the generator comes on and when it is turned off.

An automatic transfer is nice because on my old one, it would exercise the generator monthly if you had it set up to. Also, it will not kick over the the generator until a time period had elapsed without utility Power. Likewise, it wouldn't kick off of generator power until utility power was stable. But again, I can do that myself.

You can do the entire installation yourself, but I don't recommend it unless you are completely comfortable with electricity and have a healthy understanding of what you are doing.

Bottlerocket said:

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So, while i might be able to install the actual interlock switch on the panel myself, looks like I still need a professional to install the plug-in outlet and wire that to the two panel circuits that are allowed to switch to generator power when the interlock is engaged . It's not simply the interlock device itself. Do I have that right?

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If you can do the interlock, you can do the inlet plug.

So, looks like if I were to go the Interlock route on my breaker box, I'd just need to buy the Interlock and then have an electrician wire in the generator at the 1 & 3 slots below the 200A main breaker?

I believe that's correct but Need an expert weigh in definitively. I've got breakers in all my top slots just below the main; I have empty circuits at the bottom of the panel so it looks like I would need an electrician anyway to move some of those circuits around

As posted on another thread, I have the interlock, with my gas heat it was nice to be able to throw various breakers and run different parts of the house as needed with a 2300kw genset. I am too cheap to splurge on a whole house genset as the ROI isn't there for me so the interlock gave me the most flexibility for minimal investment. I looked with a coworker today and found them from $18 to $60 on amazon.


As a side note, my UPS guy had 15 generators on his truck when he stopped by the house today was expecting more tomorrow.

No sir, I added a link to a standard double throw disconnect.

Its a separate device from the panel. An interlock is an add on to your panel that physically keeps you from energizing the main breaker when supplying power from the genset.

They serve the same basic function but in different ways.

That is what the electrician who installed my 30a genset breaker had to to, moved my 40a range breaker to the bottom, thankfully it had enough wire and he didn't have to move every breaker on that side.

If you are not comfortable moving breakers, hire an electrician to do the entire job. The amperage you are working with can kill you if you put your hand in the wrong place.

That said, trust be verify! Just because an electrician installed it doesn't mean its right.

We did a mach disaster test at a bank in the Houston area. We brought in a 212kva genset. I restrapped it to 480v. Tested the voltage at the cam locks on the genset. All good. My guys hooked the leads into their transfer switch but failed to meter the switch first to verify it was installed properly. When they threw the switch, they backfed 480v utility power to the genswt and blew all the diodes. When I got there I metered the transfer switch and found the electrician who installed it had incorrectly hooked the utility feed to the load side of the switch.

skelso said:

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No sir, I added a link to a standard double throw disconnect.

Its a separate device from the panel. An interlock is an add on to your panel that physically keeps you from energizing the main breaker when supplying power from the genset.

They serve the same basic function but in different ways.

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Thanks

That is what I did, but I didn't buy the interlock. I installed the 2-pole 30amp breaker in the 1/3 slots and ran a cable and installed the 30amp outlet next to the box. Very simple. To run the generator, I flip every breaker including the main off. Start the generator and let it warm up then plug it into the wall. I flip the generator breaker on and then the breakers I want one by one. Of course, always leave that main OFF until power is restored.

mandevilleag said:

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That is what I did, but I didn't buy the interlock. I installed the 2-pole 30amp breaker in the 1/3 slots and ran a cable and installed the 30amp outlet next to the box. Very simple. To run the generator, I flip every breaker including the main off. Start the generator and let it warm up then plug it into the wall. I flip the generator breaker on and then the breakers I want one by one. Of course, always leave that main OFF until power is restored.

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This is the absolute worst thing you can do! All it takes is one time that someone forgets the leave the main breaker off and you're backfeeding power to the utility line that workers are likely trying to fix.

23% THD

Mr. AGSPRT04 said:

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23% THD

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I saw that too... yeesh. Just make sure you run any sensitive electronics through a UPS or good surge protector.

Also - for the guys installing the interlock kit or a two pole transfer switch... what are you doing with the neutral if it's bonded at the generator making it a separately derived system? Are you switching it too? Or just disconnecting the bond on the generator frame?

With an interlock the only switching you are doing is with breakers, so the neutral is not affected. In that scenario you need a generator with a floating neutral (or need to convert it before connecting it) to avoid double grounding.

SaluteTheMarines said:

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What generator? Fuel source?

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Generac 15KW natural gas.

skelso thats what i was thinking. Big NEC no no to have two bonds. They'll need to disconnect the NG bond on these bigger generator frames to avoid parallel paths.

How does net metering work in a situation where the power drops? Will the meter block any output if it doesn't have main line electricity or will the excess home electricity flow back down the line?

There must be an interlock device between your panel and the main such that any power generated on site doesn't backfeed the service lines. This is a key safety requirement. Your meter should never see any of the power coming from a generator.

This is an entirely different level of discussion, one that I dont have much direct experience with. That said, here's a few things I do know.

1) Before you can interconnect for net metering, you have to sign an agreement with your utility company. During that process they will examine your system and approve requirements specific to it.

2) Net metering systems are prohibited from generating electricity during a utility outage. There are several means to ensure this but the basic principle is if the device doesn't sense utility power, it opens the circuit so no power flows.

I've been researching generators as well, and although the ROI on a Generac whole home generator doesn't add up, the peace of mind will probably win out.

That said, if I'm going to make the investment, I also want a 'Plan B' of sorts in case the Generac option fails, or has issues at the moment of need. Research to mitigate this concern turned up this nifty little device:

http://www.generlink.com/

It's a tansfer switch that allows you to simply power your existing home breaker box via a portable generator.

In my case, it will be insurance in case the generac doesn't work when needed. But the other, more practical application is to simply allow a portable generator to power your breaker box with minimal complexity and cost.

SaluteTheMarines said:

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What generator? Fuel source?

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Wen 3800 - gas.

I think I could pull off the wiring, but this is going on exterior brick wall & I don't want to dork up the masonry.

I think this would be the right place to discuss my parts list towards installing a 50A power inlet. I am not necessarily going to buy all from Amazon, but have it to show the parts. Most inlets I have looked at do not have a top knockout, so that's why there is an elbow to go into the side. This will be done on a rear exterior brick wall.

Existing Breaker box: Eaton BR 125 A, main breaker in top 2 left slots

Breaker: Eaton BR 50A (to be installed across from main, top 2 right slots) https://www.amazon.com/gp/product/B000BQUGUC/ref=ox_sc_saved_title_7?smid=A1KN65RUO4HE9O&psc=1
Interlock: Eaton BRMIKBR https://www.amazon.com/gp/product/B00JV3ESD2/ref=ox_sc_saved_title_6?smid=A2EF9C7PMOMPR8&psc=1
Conduit from panel to Inlet: 3/4" Halex Rigid Elbow https://www.amazon.com/gp/product/B00N6WMXXQ/ref=ox_sc_saved_title_3?smid=AZHZ102UTKBMA&psc=1
Conduit locking nuts: (Inside the breaker box and power inlet) https://www.amazon.com/gp/product/B00286FHNY/ref=ox_sc_saved_title_2?smid=A2N4L2KGMLRTBM&psc=1
Wire: 8AWG, 4 wires (black, red, white, green) in needed length https://www.amazon.com/gp/product/B07TCJNB51/ref=ox_sc_saved_title_1?smid=A3772S73Y6750L&psc=1
Inlet: https://www.amazon.com/gp/product/B08GLK5HJJ/ref=ox_sc_saved_title_4?smid=A27WQG1FRAMCEJ&psc=1

Whats the best way the inlet to attach to the wall, just some lag shields and bolts, then caulk it? Am I missing anything, or anything on here not to code/spec?

That's pretty interesting but man, way more expensive than just putting an Interlock in the breaker box