Using on board generator as stand by power for sticks & bricks

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Using on board generator as stand by power for sticks & bricks

November 12, 2012, 11:37:22 am

Can anyone tell me what's involved in using my 10KW PowerTek to supply electricty to an esisting manual transfer switch in my house ? Will I need to add a manual transfer switch in the coach ?

Thanks,

Jon Harris

Re: Using on board generator as stand by power for sticks & bricks

Reply #1 – November 12, 2012, 12:24:16 pm

Jon,

You will certainly have to have a manual transfer switch in the line from power company to house. You have to absolutely make sure that you can not back feed the power company line, as when power is down there will be repair men working on it. If you back feed, you could electrocute them.

Brett

Re: Using on board generator as stand by power for sticks & bricks

Reply #2 – November 12, 2012, 02:18:48 pm

Quote from: wolfe10 – November 12, 2012, 12:24:16 pm

Jon,

You will certainly have to have a manual transfer switch in the line from power company to house. You have to absolutely make sure that you can not back feed the power company line, as when power is down there will be repair men working on it. If you back feed, you could electrocute them.

Brett

The best way to prevent that is to turn off your main breaker where your power comes in to your house

Re: Using on board generator as stand by power for sticks & bricks

Reply #3 – November 12, 2012, 02:27:36 pm

Safer and to code to have a switch that switches not only the two hots, but neutral as well. Therefore a manual transfer switch.

Re: Using on board generator as stand by power for sticks & bricks

Reply #4 – November 12, 2012, 02:48:37 pm

Sounds like Jon already has a transfer switch on the power company side ..... mighty handy. Brett: For those of us who do not have that switch (or in some cases, not even a master breaker in the breaker box) methinks one could just snip the seal, remove the meter from its base and run on coach power until any commercial power problem is resolved? Power companies don't really like that a lot, but when we occasionally had to do work on the bus bars in a customer's ckt breaker box (in my residential AC business) we would temporarily pull the meter, do our work....then replace it; and we never did get even a "growl" from them. They always just put a new seal on at the next meter reading time and said nothing......and no, I have never been in jail (maybe just lucky?)

FWIW

Ed Sievers.....still lurkin' at FTs (and reading every post in this great forum.)
Fairview, TX

Re: Using on board generator as stand by power for sticks & bricks

Reply #5 – November 12, 2012, 06:02:20 pm

Unless I missed something, John's question was not answered. Recognizing that one definitely needs to protect back feeding to the public electric system do you need a transfer switch on the Coach Generator. If the public power comes on while the coach generator is hooked to the house system, will it harm the coach generator? Will the home transfer switch protect the coach generator.

Re: Using on board generator as stand by power for sticks & bricks

Reply #6 – November 12, 2012, 06:56:58 pm

When did switching neutral become a code issue ?? NEC does not require it, no electrical contractor, nor inspector seems to know this.
In some commercail setups, an overlapping neutral switch is used on 3 phase, I have used a 3 pole switch and switched neutral in a rare case.
In most cases a solid neutral is normal, so I am wondering where this comes from?
Thanks
Dave M

Re: Using on board generator as stand by power for sticks & bricks

Reply #7 – November 12, 2012, 06:59:29 pm

Quote from: Jon H – November 12, 2012, 11:37:22 am

Can anyone tell me what's involved in using my 10KW PowerTek to supply electricty to an esisting manual transfer switch in my house ? Will I need to add a manual transfer switch in the coach ?

Thanks,

Jon Harris

I added a 50 amp outlet from the Generator off of the coach Transfer switch.
You can add a 50 amp male plug from your house transfer switch and plug it in.
You can also power another RV in trouble if their Gen is not working like in Quartzsite.

Re: Using on board generator as stand by power for sticks & bricks

Reply #8 – November 12, 2012, 07:01:57 pm

For an in extremis situation, Ed makes a good suggestion, pull the meter and blank off the cover. That eliminates any chance your generator can backfeed the grid. It also prevents problems with suddenly dealing with out of phase power. I've never been barked at for doing this but depends on your jurisdiction.

Beyond that, the next issue to deal with is the fact that your generator is set up to generate 120 Volt rather than the 240 the house is set up for. I believe the generator can be modified to produce two out of phase legs which would give you 240. Seem to remember someone having Powertech do this. Things like home heating systems, well pumps, air conditioning are often going to need 240. If you're set up for 240 4 wire from the coach generator then you're good to tie in and go.

Sure, you can install a dedicated ATS on the house and rig your autostart but how often would you really need this capability? Simplest thing to do might be flip off the main breaker and run some heavy extension cords from coach to house to power strips, plug in what you need.

Re: Using on board generator as stand by power for sticks & bricks

Reply #9 – November 12, 2012, 08:20:02 pm

If you turned off the Main or unplugged the Meter, is there a reason one couldn't hook up a 20 or 30 amp, 120V heavy duty extension cord to a 120V outlet at the house? The main things I would want to run would be the refrigerator and the blower fan on the furnace.

Re: Using on board generator as stand by power for sticks & bricks

Reply #10 – November 12, 2012, 10:16:15 pm

Hi All,
Thanks for all the responses. To clarify - the new Florida S & B was originally built (2004) with a 200 amp manual transfer switch (see attached picture) - but no standby generator. Can't see spending $$$$$ when there's a perfectly good 10 KW diesel generator parked in the yard

. Didn't know what modifications were appropriate in the coach in order to provide 220 single phase to the house. Do I need to isolate the coach circuits while providing power to the S & B ?

Re: Using on board generator as stand by power for sticks & bricks

Reply #11 – November 13, 2012, 04:37:05 am

Jon, You have a good setup with that manual DPDT switch, if you do not have any 240 volt loads such as well pump, oven, water heater, heat or a/c and you only NEED 120 volt, and guessing your generator is setup for 120 Volt and not 240 V, you could simply run a heavy S/O 6 ga / 4 conductor between coach and the switch on wall, wire 120 to both lugs on the emergency/generator side of switch. You only get 120 volt on both legs, just no 240 VAC.
IF you need the 240 volt, then you will need to reconnect the generator leads for the 240 v. How is your coach setup at the ATS 120 volt from genset or 240 V ?
The feed from the outside post on the 50 amp setup is 120/240 volt.
I just hate running a genset with the 120/240 volt setup due to unbalanced loading per leg, also reduces the starting current for a/c and other incuctive loads.
Genset is either 41.6 amp (240 V) or 83.2 amp (120 V) per leg.
Just some thoughts
Dave M

Re: Using on board generator as stand by power for sticks & bricks

Reply #12 – November 13, 2012, 05:39:49 am

Jon, seems like the folks to call first would be Power Tech in Leasburg, Fl. They can answer any questions about adding the needed receptacle to your gen set to get the 240V you need, then it's just a matter of getting the power to where you need it, any licenced electrician can take it from there. Looks like your transfer switch at the house is there for that reason. With that said when the storms hit us in 03/04 all we did is shut the house completely off and fired up the motorhome until power was restored. All the systems in the coach will work on your generator, only a few in the house (on at one time) will work off of the 50A generator in the coach, we where quite comfortable for several days without power.

Re: Using on board generator as stand by power for sticks & bricks

Reply #13 – November 13, 2012, 11:15:52 am

Another thing to be aware of, overload. Example, I have a 45 kw standby generator, but I can't run the whole house. The electric furnace had to be blanked out from running before the inspector would sign off.

Re: Using on board generator as stand by power for sticks & bricks

Reply #14 – November 13, 2012, 11:19:49 am

Quote from: Chuck Pearson – November 12, 2012, 07:01:57 pm

For an in extremis situation, Ed makes a good suggestion, pull the meter and blank off the cover. That eliminates any chance your generator can backfeed the grid. It also prevents problems with suddenly dealing with out of phase power. I've never been barked at for doing this but depends on your jurisdiction.

Beyond that, the next issue to deal with is the fact that your generator is set up to generate 120 Volt rather than the 240 the house is set up for. I believe the generator can be modified to produce two out of phase legs which would give you 240. Seem to remember someone having Powertech do this. Things like home heating systems, well pumps, air conditioning are often going to need 240. If you're set up for 240 4 wire from the coach generator then you're good to tie in and go.

Power Tech told me some time ago to change our 10k Gen to 220vac just reverse 2 wires and remove a jumper as seen in the below photo.

Re: Using on board generator as stand by power for sticks & bricks

Reply #15 – November 13, 2012, 11:26:28 am

Barry,

I don't see the " below photo".

Re: Using on board generator as stand by power for sticks & bricks

Reply #16 – November 13, 2012, 11:33:23 am

Quote from: Jim Frerichs – November 13, 2012, 11:26:28 am

Barry,

I don't see the " below photo".

Look Closer

Just kidding. I am again in a terrible wifi site and had to try uploading the photo separately It is there now. I have lost several messages that I tried to upload and it would not go thru

Re: Using on board generator as stand by power for sticks & bricks

Reply #17 – November 13, 2012, 08:20:56 pm

When 'unofficially' connecting a generator to a stick-home, pulling the meter does nothing more electrically than turning off main breaker, as neither disconnects neutral wire.

Turn off main house breaker, use a double male cable, connect generator to a 220-volt outlet, often found behind dryer or under kitchen range-top. This powers both house hot wires and one just needs to manage house loads to stay within generator capacity. This common method is not within code and it is VERY important to be sure main breakers cannot be turned on with generator connected. Some have installed female outlets on each leg in a convenient location, to be used to connect generator. The maximum current will be limited by the circuit breaker on the outlet being used.

Re: Using on board generator as stand by power for sticks & bricks

Reply #18 – November 13, 2012, 09:40:57 pm

It is truely amazing how many folks are wanting to meet the judge, geez, yes YOU know how to turn off a breaker and connect the generator using a home made cord to the dryer for example, BUT consider when you are not there due to what ever reason, the power goes off, and your bunk buddy sez gee lets see, I plug this into here and not turning off the breaker, you could meet the judge and do your very best to teach him how it could not have been your setup that fried the poor worker down the line because you were too cheap/dumb to do it correct. Oh joy. And the power company know who has a generator.
Working in the generator field, you get some real engineering examples of stupid.
Joh has the safety DPDT transfer switch, that is correct, and congrats Jon.
Thinking is still a smart art.
FWIW
Dave M

Re: Using on board generator as stand by power for sticks & bricks

Reply #19 – November 13, 2012, 11:18:57 pm

One of the jobs I had during electrical outages was what we called preflight ,looking over damaged service areas ,yellow barrier taping off downed wires, estimating crews for Restoration, and later restoring temporary power to homes and businesses with bad service drops. When we heard a generator running we where drawn to them like they where magnets. Inspected installation had a green tag and the home owners for the most part liked to tell us all about them. Uninspected hook up where shut down before we left . The ones that used cords to individual appliances where OK after we talked to the home owners.Gam

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