Honda generator and electrical grid

[cgmartine]

Might I ask a question here unrelated to motorhomes? The topic of portable generators often comes up here and on other forums. I am thinking of buying the Honda "Companion" portable generator, and I am wondering if there is a way, in the event of an emergency, to connect it to the house directly, by having an electrician wire up something like a 30 amp receptable to the house, where I would then plug in the 30 amp cord directly from the generator, to eliminate a bunch of electrical cords to the various items I would intend to power. I know I would be limited to just a couple of items unless I had a second generator, which I am also contemplating in buying. Has anyone done this?

[theoldwizard1]

pianotuna wrote:
Set up a proper transfer switch. I had a nice six circuit manual one in my home. It was quite handy.

And this is what I DO NOT like about those ! You have to PICK your 6 circuits !

Why ? I am smart enough to "manage" my loads. If I want to go to the back bedroom and watch TV there, no problem, as long as I am not going to exceed the capacity of my generator !

If I have a load (extra freezer) that is intermittent, I can unplug something (like the main refrigerator) and then run the other load for a few hours and switch back. Heck, you can run a well pump (if you have a 240V generator) and wash clothes (probably with cold water). You might even be able to heat a heat a tank of water with everything else turned off !

[time2roll]

Just hire an electrician. It will work fine and comply with all city and utility requirements to be safe in all conditions.

[westend]

It takes many thousandths less power to electrocute someone than it does to trip a breaker.........

Especially when the neutral potential is fed back through the utility's transformer.

[JaxDad]

DrewE wrote:
What you say about surges doesn't make any sense to me.

It doesn't make sense to me either, because I didn't mention surges.

I think the problem you are having with this is that it depends on whether, according the NEC terminology, the generator is a "Separately Derived System" or a "Nonseparately Derived System" and then code dictates whether the bond must stay in place, or be removed. See sections 250.30(A)(1) and 250.30(A)(2).

The bottom line is that in very real and possible circumstances messed up wiring and or appliances could cause the rest of the supposedly 'dead' system to have potential in the neutral ground system.

A lot of people assume that since the neutral and ground are bonded there's no or little risk, this is based on the 'path of least resistance' theory, HOWEVER, that does NOT mean that other paths don't have any load on them, just that the 'least resistance' path is taking (proportional to resistance) a lesser amount.

It takes many thousandths less power to electrocute someone than it does to trip a breaker.........

[sherlywang]

Honda is famous, maybe better than Cummins,I think. I'm happy with mine. how ever it's important to remember that power from propane will cost you double the cost of power from diesel fuel as propane has a lot less "energy" when compared to diesel.

[sherlywang]

I purchased a 13,750kw Propane Generator from Central Maine Diesel a few years ago.

20 HP Honda engine, Italian generator head.
Paid about $2300 plus shipping via Paradise Freight which was a few hundred.
I see the price is just a bit higher now... But the one I want most is Cummins which i saw from a website.

Recently it blew a capacitor. Central Maine sent me 2 for the price of one even though it is out of warranty. $39 total for two.

I looked at generators on island but a similar Honda at Quality electric was close to $6000 and it wasn't even a 13750kw. More like 8 or 9000kw if I remember right.....

They have many generators at great prices but this is the one I settled for.

Quiet, no smell, propane lasts forever........

[DiskDoctr]

Here's a video on a Square D manual interlock.

video

[KCFDCapt]

I have a 22 kw standby generator with an automatic transfer switch. When the electrician installed it, he installed a manual disconnect with a lock out feature on it. That is so a lineman can throw the disconnect and put his padlock on the handle to keep any one else from energizing the line. That set up today will run about $5 K installed.

[DrewE]

JaxDad wrote:


No, it does NOT do the same thing.

The ground and the neutral are bonded in the breaker panel and meter base. Backfeeding the house without breaking that bond means there is potential in the neutral wire beyond the meter base and back out into the grid.

A typical breaker doesn’t kick over with enough force to trip a second breaker, add to that the fact that it requires a massive overload to trip a breaker on a short circuit condition, not just a simple overload, like 5 times the normal load to trip.

If you haven’t transferrred the neutral, that massive overload could, and likely will, pass through the meter base and out into the grid.

I think you don't understand how the interlock works. It doesn't do anything to impede the tripping of a breaker. Rather, it makes it physically impossible to turn on or reset more than one of the interlocked breakers at any time. Before the generator one can be reset, the main must be disconnected, and vice-versa. It doesn't prevent or impede them from both being tripped simultaneously.

What you say about surges doesn't make any sense to me. Yes, the panel will typically bond neutral to ground (or, if not the panel, someplace at the service entrance they will be bonded together). That is the only place they get bonded; the generator output is floating otherwise. Any surges would be between the legs and the neutral, not between neutral and ground, and as the legs are disconnected from the rest of the grid (since the main breaker is off), they will not backfeed anything. Neutral will just sit at ground potential; indeed, it can't do much else since it's bonded to ground.

Incidentally, transfer switches for standby generators for houses do not typically switch the neutral line. Transfer switches for RV generator installations do because the RV panel doesn't bond the neutral and ground (as it acts as a subpanel when connected to campground power) and the RV generator does (so they are bonded when operating under generator power); it's needed there to maintain the standard that they are bonded at only one location.

The circuit breaker interlock systems are approved transfer switching mechanisms. The NFPA and UL accept them as safe for this application, and many of the dedicated manual transfer switch panels sold for household use employ circuit breaker interlocks as their switching mechanism. I'm very willing to believe that those organizations collectively have a better idea of what's safe and what isn't than you or me or any other posters here.

[pianotuna]

Set up a proper transfer switch. I had a nice six circuit manual one in my home. It was quite handy.

[theoldwizard1]

There is more than 1 solution to this problem.

The lowest cost of installation with the most flexibility for running various different lights and appliances is some called a "generator interlock kit".

It does require common sense to use.

[JaxDad]

Dutch_12078 wrote:

Dusty R wrote:

JaxDad wrote:

cgmartine wrote:
The third option, the breaker interlock, is exactly what I pictured in my mind. I believe I could do it myself, but just to be extra safe, I will hire an electrician to do it for me.

I’d be surprised if you could get an electrician to do that sort of a job. It’s not legal because it’s potentially very dangerous.

Please do it properly and install a transfer switch.

A breaker interlock does the same thing as a transfer switch, and is legal.

Exactly... The interlock doesn't allow the generator supply breaker to be turned on until the main line breaker is turned off, and vice versa.

No, it does NOT do the same thing.

The ground and the neutral are bonded in the breaker panel and meter base. Backfeeding the house without breaking that bond means there is potential in the neutral wire beyond the meter base and back out into the grid.

A typical breaker doesn’t kick over with enough force to trip a second breaker, add to that the fact that it requires a massive overload to trip a breaker on a short circuit condition, not just a simple overload, like 5 times the normal load to trip.

If you haven’t transferrred the neutral, that massive overload could, and likely will, pass through the meter base and out into the grid.

[kerrlakeRoo]

Short answer,,,,,, Yes you can.
The right way to do it is with a transfer switch to eliminate the possibility of your generator applying power to anything outside your house.
A couple of years ago we had snow knock power out for an extended period, I wired a construction genny with 230 volt outlet to my well circuit. It powered both AC legs in my house and ran everything, but I KNEW I had the main cut off both at my main panel, and at the outside panel where my meter was located. THIS IS NOT A RECOMMENDED METHOD,
I only tell you this to explain that even a 4500 watt construction genny will run a house, I could run everything except my dryer, hot tub, and heat pump.

[MrWizard]

You need an approved lockout transfer switch
Either manual or automatic
That prevents power from being back feed to the utility grid

A simple plug , is an illegal NoNo

[SAR_Tracker]

ktmrfs wrote:

owenssailor wrote:

SAR Tracker wrote:
Here in Central Oregon, we have "emergencies" once in a while.

I really hope you shut off the main beaker to your house when you do a jury rigged approach like this. Otherwise you can send 120V power out to the lines where people are working. This could hurt or kill them!!!!!!!!

ah..... what the OP described is safe. by using a power strip NOTHING is connected to the house electrical system. He's NOT using any inside outlets connected to the panel.

Zactly! Very familiar with feedback to the grid. Power strip is connected directly to the extension cord, which is connected directly to the generator.