Running House off of RV Generator

abn · 08-18-2008, 06:16 AM

Is it possible (and/or adviseable) to hook the RV electric supply cable (normally an input from an external box) to an input box for the house so as to use the RV generator as an electrical supply when the power goes out?

In other words, will power feed out thru the input cable and not harm the RV by doing so?

Where we live the power gets knocked out a lot. We do have a generator for the house and the house is wired for it. I was just wondering if I could use the RV as a secondary backup for that generator.

abn · 08-18-2008, 06:16 AM

Is it possible (and/or adviseable) to hook the RV electric supply cable (normally an input from an external box) to an input box for the house so as to use the RV generator as an electrical supply when the power goes out?

In other words, will power feed out thru the input cable and not harm the RV by doing so?

Where we live the power gets knocked out a lot. We do have a generator for the house and the house is wired for it. I was just wondering if I could use the RV as a secondary backup for that generator.

Stevegd007 · 08-18-2008, 06:36 AM

abn, not adviseable....unless you have a cutout switch on the house to cut power from the genset going out to the power company lines. This would be an isolater (sp), not the main power breaker on the house electrical panel. If you fail to install any kind of isolater you risk engerizeing (sp) the power lines leading from you house and possibly harming some electrical worker hanging off a power pole somewhere down the line.

I do use the genset to power limited household appliances, i.e. refer, freezer, TV and lights if needed. I run a long extension cord to a power cord spliter and then to just the actual appliance. Never to the household outlet which would then lead out to the power company lines.

Route 66 · 08-18-2008, 06:49 AM

I agree with Steve that with proper transfer switches, it is certainly doable.

Eddie Foy · 08-18-2008, 09:04 AM

Tripping the main on your house panel isolates you from the grid. No isolator required.

Using your RV genset is doable.

RustyJC · 08-18-2008, 10:43 AM

The following is worth a read - TRANSFER SWITCHES.

Rusty

GaryKD · 08-18-2008, 10:46 AM

Hi abn,
I am set up to do this. I had an electrician install a transfer switch. A female 50 AMP socket has been installed in the electric bay of the coach and on the house. The socket is live only when the generator is running. When power is applied to the house receptcale the transfer swith kicks in and certain circuits in the house are now live. The transfer switch also isolates my house from the electric company power lines. I can power all 110V house circuits, with the generator. All house 220V circuits remain off.

John_Canfield · 08-18-2008, 11:50 AM

The big hurdle to overcome is getting a feed from the coach - you would need another transfer switch in the coach to connect power directly to the external load (house in this case.) Like somebody else mentioned, to isolate the house from the mains you simply flip the main breaker to the 'off' position.

At our last house in Florida, I used my 50 amp welder outlet to backfeed the house with my portable Honda generator (after switching the main breaker off of course.) Lots of people use the dryer outlet to backfeed as well. We used this system with great success for several 'wind events' (hurricanes.)

RustyJC · 08-18-2008, 12:35 PM

I would strongly suggest checking with your local building inspectors as either manual or automatic transfer switches that make it impossible for the house to be connected to the generator and grid simultaneously are generally a legal requirement.

If, as you say, the house is already wired for a generator, you hopefully have this covered. If others are considering this, almost all localities have legal requirements for wiring for standby generators.

Rusty

codgerbill · 08-18-2008, 02:12 PM

I had retired from an Electric Utility in SE Michigan after 43 years. I can say that your generator will attempt to power everything connected to it, until it gets into an overload condition. If your load is not isolated from the utility the generator will attempt to power the neighborhood. The safety problem is that if there is very little load your generator could backfeed the system (including the utility wires on the pole) and a unaware person thinking that a wire dangling down may be at hazard.
If I had a power outage I would isolate my unit from the utility with a transfer switch or just run an extension cord to the few items you will need power on (Furnace, Freezer, refrigerator, Etc.) The downside to non isolation, other than the safety factor is that when the utility service is re-energized your generator will operate in parallel for perhaps a few milliseconds before it launches itself

John_Canfield · 08-18-2008, 02:39 PM

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by codgerbill:
I had retired from an Electric Utility in SE Michigan after 43 years. I can say that your generator will attempt to power everything connected to it, until it gets into an overload condition. If your load is not isolated from the utility the generator will attempt to power the neighborhood. The safety problem is that if there is very little load your generator could backfeed the system (including the utility wires on the pole) and a unaware person thinking that a wire dangling down may be at hazard.
If I had a power outage I would isolate my unit from the utility with a transfer switch or just run an extension cord to the few items you will need power on (Furnace, Freezer, refrigerator, Etc.) The downside to non isolation, other than the safety factor is that when the utility service is re-energized your generator will operate in parallel for perhaps a few milliseconds before it launches itself

</div></BLOCKQUOTE>Bill - actually it is quite safe if you are careful, understand the technical situation and follow a set procedure. No way would I recommend this to somebody that doesn't appreciate the risks involved.

The primary safety consideration is to never ever turn on the main breaker while you are powering your home from the gen set.

I marked the breakers that were to be turned off before switching the house load to the gen set. In fact, I made a check list of the exact sequence and procedures to be followed. I did this primarily for our house sitter who would live in our house while we traveled.

There was never a problem about contention when neighborhood power was restored and we're still on generator because if I suspected that power was restored (a visit with my neighbor), I would shut off my gen set, shut off the 50 amp feed breaker, and only then turn on the main breaker.

Bill is right - for the person that doesn't want to be intimately involved with a generator house-feed kludge, go with a transfer switch. For those of you that understand the electrical scenario and can make and follow a checklist, doing it with a backfeed through a breaker is perfectly doable and safe.

Eddie Foy · 08-18-2008, 03:57 PM

Transfer switches make it idiot proof.

After 4 hurricanes and being without power I backpower the house thru the garage sub panel after first making sure the main breaker to the grid is off.

I turn all breakers off and turn on the ones I want to power.

No danger to linemen if you do this.

wagonmaster2 · 08-18-2008, 05:36 PM

Did anyone ever answer the original question? If so I certainly missed it. abn wanted to know if its possible to use the coach power cord to hook-up to the house and power it with the generator. I don't think the generator puts power out the coach cord does it, power only comes in the cord not out? I've never tried it but didn't think things worked that way. I've been told there must be a plug-in directly at the generator, is this right? I'd like to be able to use the generator the way abn asked about. Know very little about coach electrical system, so all information greatly appreciated.
Wagonmaster2

NeilV · 08-18-2008, 06:08 PM

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by abn:
Is it possible (and/or adviseable) to hook the RV electric supply cable (normally an input from an external box) to an input box for the house so as to use the RV generator as an electrical supply when the power goes out?

In other words, will power feed out thru the input cable and not harm the RV by doing so?

Where we live the power gets knocked out a lot. We do have a generator for the house and the house is wired for it. I was just wondering if I could use the RV as a secondary backup for that generator.

</div></BLOCKQUOTE>

You can use the RV generator but must by code in most juristictions have a female receptical installed on the RV to supply the power and not backfeed it out the male cord end. You also need to have by law in most juristictions an interlocking transfer switch that will not allow you to accidently backfeed power into the electrical grid. When you turn it to the generator feed it has to automatically disconnect you from the power grid and vise versa. This is a basic safety regulation and if there is no local code covering this then I believe that the national electrical code will then come into play.

We are human and prone to make mistakes and forget things. The code on transfer switches is just good sense and a protection for all.

TXiceman · 08-19-2008, 03:03 AM

The transfer switch is a safety necessity. One thing not brough up here is that most houses are wired with 240 volt power and split into two 120 volt sets of fuses to balance the 120 volt load between the legs. You need to be sure and bring out the power from the motorhome so that you tie in to the correct leg(s), unless your generator is set up for 240 volts.

In short, the generator in the motorhome can be utilized to power some of the house circuits, but you need to know what you are doing or hire a certified electrican to do the work.

Ken

David K · 08-19-2008, 05:37 PM

SECOND all of the people above stating that you do not want to back feed on the utility lines. I have a transfer switch that I use for my generater when I need to feed the house current and I also have a master cut off switch right after the meter base outside of the house that is cut off before I actually plug in the generator. I want to make double sure that I don't electricute some utility worker that is working on the power lines near my house.

codgerbill · 08-20-2008, 06:46 AM

Another thought. In order for a generator on the coach to power the stick home, safety considerations aside, the generator needs to have the capacity.If your coach has a 4000 watt gen set as versus a 12,500 watt unit it would make a big difference. As John suggested in an earlier post, if you are considering powering load in the stick home you might first want to determine what load is "critical" (Furnace/refridgerator/freezer/etc)to your home and label the breakers accordingly. You might also have an electrician wire in a 3 position switch and have the "critical circuits wired into that. One side of switch is normal feed and the other a connection for a gen set.

David K · 08-20-2008, 04:17 PM

codgerbill -- what I did was to put in another breaker box and that is what the generator goes to. I switch off all the breakers in the main box when a power failure happens -- also kill the main switch to get the house off line -- like I mentioned above. Then from the secondary breaker box there are #12 wires running to the breakers in the normal house that I want to run from the generator --- when I switch them on, the circuit for the house is hot and runs what ever is on that circuit. With the breaker being off it does not make the buss bar hot for the house breaker box. The jumper wires go into the same place as the normal wires.

NeilV · 08-20-2008, 06:16 PM

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by David K:
codgerbill -- what I did was to put in another breaker box and that is what the generator goes to. I switch off all the breakers in the main box when a power failure happens -- also kill the main switch to get the house off line -- like I mentioned above. Then from the secondary breaker box there are #12 wires running to the breakers in the normal house that I want to run from the generator --- when I switch them on, the circuit for the house is hot and runs what ever is on that circuit. With the breaker being off it does not make the buss bar hot for the house breaker box. The jumper wires go into the same place as the normal wires. </div></BLOCKQUOTE>

Unfortunately that arrangement while it may work does not meet code or insurance regulations in most juristictions. It has to be an interlocked transfer switch with no chance that you could have both switches turned to the on position even for a moment.

KCE · 08-20-2008, 07:29 PM

[quote]The primary safety consideration is to never ever turn on the main breaker while you are powering your home from the gen set.

I marked the breakers that were to be turned off before switching the house load to the gen set. In fact, I made a check list of the exact sequence and procedures to be followed. I did this primarily for our house sitter who would live in our house while we traveled.

There was never a problem about contention when neighborhood power was restored and we're still on generator because if I suspected that power was restored (a visit with my neighbor), I would shut off my gen set, shut off the 50 amp feed breaker, and only then turn on the main breaker.

I agree with you John I've been doing it that way for 18 years and have never had a problem. If you don't know what your doing install a transfer switch.