30 A restriction, when connected to 50 A service

[ronnie_g]

The first year I had my new to me motor home we ended up wintering in Denver CO. My thoughts were to try to heat the RV as much as possible using multiple 1000W electric heaters. As I didn't want to go through the problems with renting an external LP tank.
Think if I did it again, we would just rent a large tank....
Anyway shortly after I set up all the heaters I found myself w/o any electricity? All the breakers where OK and I had power where we were plugged in. It took me a good 30 min to discover the inverter has a 30 A breaker that was tripped.
The way my motorhome is wired.
I have 50 A service coming into a 50 A breaker, then I have a sub panel with a 30 A breaker and breakers for all (I think all) of the outlets and the microwave.
I can grasp the desire to have as much stuff as possible on the inverter knowing you are not going to run it all at once.
BUT in my case, turning on the Microwave or the coffee maker would reliable trip the 30 A breaker.
End result we are limited to 30 A service on the outlets / appliances.
Has anyone done anything about this?
I was considering adding more 15 A breakers in the main panel.
Then use 15 A 3 way switches to switch the load off the inverter when I wanted to be able to run more than 30 A total load.

NOTE: We made it through the winter OK, ran 5 1000 W heaters (on low) to conserve LP. Had 3 in the living area, and 2 in the storage.
Bought a small external bottle to avoid having to drive the RV across town to buy LP.

[Tony Lee]

Usually there are some outlets running through the inverter and some running direct so you can get 30 amps from one set of outlets and more from the other set. On my MH the outlets are marked if they run through the inverter. Air-conditioning is usually run direct so you could install a couple of dedicated heater circuits teed off from those since both heating and cooling won't be run at the same time.

[Triker56]

NOTE: We made it through the winter OK, ran 5 1000 W heaters (on low) to conserve LP. Had 3 in the living area, and 2 in the storage.

I use the wheels on my MH and drive it south to where it is much warmer, where it only takes 2 1200W heaters(1 front 1 bedroom) on 30 AMP hook up to keep it warm for the few nights it gets below 50º.

[TQ60]

How much work do you wish to do?

Factory look or?

You have 2 panels so sourcing your power is simple.

Getting power wiring routed maybe not so much.

The easy is to add a couple outlets for heaters connected to the 50 amp panel and be sure to stagger the feeds so load is balanced on L1 and L2.

The hard part...

You could run a second set of power wires to the existing outlets currently on the inverter supply but have them connected to the 50 amp panel.

Then in the outlet box or rather the rear of the outlet you break the tabs between the top and bottom wire connections and connect the non - inverted to one and the inverted one to the other.

SAFETY MESSAGE....
We assume inverter in standby when on shore power so make certian the source connection is on the same phase when connecting this.

Otherwise the 2 outlets will have 240 across them which is not really a concern but could be a code problem.

Do mark the outlet properly.

Heed advice of folks who do electrical work for a living as they are more aware of code requirements than us hobby type folks.

[ronnie_g]

Originally Posted by Tony Lee

Usually there are some outlets running through the inverter and some running direct so you can get 30 amps from one set of outlets and more from the other set. On my MH the outlets are marked if they run through the inverter. Air-conditioning is usually run direct so you could install a couple of dedicated heater circuits teed off from those since both heating and cooling won't be run at the same time.

Only outlet I could find (in the living area) not on the inverter was the washer/dryer. I have thought about trying to 'run' some outlets. But IMO swapping them off the inverter would be a easier / cleaner way to do it?

##########

RE: RE: so load is balanced on L1 and L2.

I just installed a surge protector that will show the load on both sides. Have not mounted the display yet.

For some time I have been thinking that most RV's were not wired to balance the load.
My 2 AC units are split, then after that....
Black: Inverter / charger and 30 A sub panel
Red: Water heater

hardware not installed:
black: dishwasher/fireplace
red:Washer/Dryer

Other than the Water heater & AC everything is on one side.....

Originally Posted by Triker56

I use the wheels on my MH and drive it south to where it is much warmer, where it only takes 2 1200W heaters(1 front 1 bedroom) on 30 AMP hook up to keep it warm for the few nights it gets below 50º.

Great thought, Cept can't move 'family problems' like that :-)
I live in FL, so heading north for winter is out of the norm.....
Some times we end up doing stuff that we wouldn't normally do...

[Gary RVRoamer]

Yeah, the 30A limit of most inverters with a built in transfer switch is a nuisance if you want to run high-amp devices. They do make inverters with larger internal breakers, though. Typically those will be models with 3000 or more watts of capacity.

I put a manual transfer switch in a previous coach so I could switch circuits on/off the inverter at will. Back then we sometimes stayed at places where only 15 or 20A site power was available, so it was handy to run some circuits on shore power and some on inverter.

[dons2346]

Install one of these Magnum Energy MSH3012M 3000 Watt 12V 125A Inverter/Charger with 120VAC Output

It has 60 amp pass through breakers.

BTW, this is the best price you will find on this unit.

[ronnie_g]

Originally Posted by dons2346

Install one of these Magnum Energy MSH3012M 3000 Watt 12V 125A Inverter/Charger with 120VAC Output

It has 60 amp pass through breakers.

That is what should have been installed would solve the problem for everyone. Out of my price range as long as the one I have is working.

I looked at the sub panel last night.
I have a 30 A breaker in the main feeding the inverter that has another 30 A breaker that feeds the sub panel with yet another 30 A beaker all of this is feeding 5 15 A breakers.
Of the 5 loads only 2 can be run at the full 15 A.
Doing the math, my coffee maker & microwave total 25 A so that leaves me +- 5 A to service the remainder of the appliances that plug in.... Try using a electric skillet and I am way over the 30 A.
To fix the root problem would require replacing the inverter plus rewiring all the 30 A breakers and panels. Not a reasonable solution.

[wa8yxm]

A comment and a suggestion:

The Comment: the QUICK BOX recepticals often used in RV's are not really all that good. Now for a 1,000 watt heater I think i'd trust them but for a 1,500.. I have had one give warning (i replaced it for safety) and others have had 'em fail.. What's worse it's not always the outlet you are plugged into that fails but one up-line.. They use something akin to the PUNCH DOWN connectors often used by the phone company, Good for the low current on a phone line. not so good at double digit amps.

What did I do?

Well thankfully on my coach the power panel (Breaker box) is well located but I put in a pair of 15/20 amp duplex recpticals These have a "T" shaped neutral slot (Laying on it's side) and genuine SCREWS to bend wire around and tighten well.

I used 12 ga wire for the short runs (one run is under 2 feet the other is about 10) and each outlet has its very own 20 amp breaker on the MAIN panel (ok, one of 'em is 15 cause that is what I had in stock).

No aroma of hot wire, No failure, No problems, Works great

NOTE: if your RV came pre-wired for a Washer/Dryer.. You may find that outlet is accessable and using a heavy duty cord you can plug into it. This one may be a 15/20 as well (Higher quality)

[ronnie_g]

Originally Posted by Gary RVRoamer

I put a manual transfer switch in a previous coach so I could switch circuits on/off the inverter at will.

Gary, your xfer switch. Do you remember if it switched Hot & Neutral or just Hot?
I was going to start looking / tracing to see if the neutral lead was common through the inverter. OR if the neutral in was isolated from the neutral out on the inverter.
My dirty solution is to use 15 A 3 way light switches as a xfer switch.
But it would only switch the Hot.
Common on the switch would be the load, then the inverter output would be on one lug, and a new 15 A breaker would be on the other lug.
This would allow me to bypass the inverter as needed. BUT depends on the neutral wire being a hard wire through the inverter.

[mojoracing]

On mine, i just turn the inverter off. I have never had a problem running an electric heater. Even though I shut mine off at the little monitor panel does that still mean that current flows through the inverter? In addition to the little off bottom on the magnum inverter remote panel, I have what looks like a battery cut-off switch mounted near the inverter. Is this used to bypass the inverter in case I find myself in the same situation as the OP?

[Okiedoke]

I added a 20A circuit in the bedroom that connects directly to the 20A shore outlet. A dedicated surface mount recepticle is installed in the bedroom wired to a heavy duty outdoor extension cord that stays coiled in the electric bay. I plug it in to shore power when using an electric heater.

[ronnie_g]

Originally Posted by mojoracing

On mine, i just turn the inverter off. I have never had a problem running an electric heater. Even though I shut mine off at the little monitor panel does that still mean that current flows through the inverter? In addition to the little off bottom on the magnum inverter remote panel, I have what looks like a battery cut-off switch mounted near the inverter. Is this used to bypass the inverter in case I find myself in the same situation as the OP?

Best way to tell if you have this restriction is to look at your main and sub ckt breaker panels. Looking at the main, do you see any outlets shown?
Looking at the sub, what is the master breaker on the sub. That determines the max current for all the other breakers. I have a 30 A master feeding five 15 A breakers. So for those 5 ckts the total can not be more than 30 A.
If I did not have an inverter / sub panel those 5 ckts could draw 75 A.
As for the battery cut off, I would assume if you removed your batteries from the inverter you would also loose your battery charger?
Your inverter should also have a 120 V ckt breaker that for me is the same as the sub panel master.

[mojoracing]

Ok. I don't mean to hijack the thread but for complete newbies to ac electrical, an explanation of this pic of my breaker box might help all of us.