Portable electric heater in coach

[LarryB]

It seems to me I was told [years ago] to never plug in a portable electric heater in the coach. One should always use an extension cord and the power post at the parking pad.

I watched an older gentlemen use the 'cord to power post procedure' last night. They were in an 06 Marathon, I'm almost sure those have toe kick heaters, but the old gent wanted more heat I guess. Cold here in Eugene, OR.

Is this something I have misplaced in my memory bank or is it an old wives tale?

[Yankee802]

Well, untill I get my Webasto figured out, I got a couple electric heaters plugged into the outlets inside the coach, why would that not be ok? They are the same thing as the toe kick heaters, just not built in.

[LarryB]

Well Yankee, That is what I was thinking as well. I don't know where this info came from or why. Just started thinking about it when I saw the guy using the power post instead of the inside outlets.

[bluevost]

Larry B,

I use an electric heater in the bus all the time. It is one of those tower models and have had no problems whatsoever.

[LarryB]

I used a portable to take the chill off while down in the desert a few years ago with on problem as well. Seems it didn't draw any more that a hair dryer etc.

I just can't figure why/where this came from. My CRS is kicking in.

[Jon Wehrenberg]

I'm trying to figure the logic of that. I think it is some OWT because the outlets in my coach are more than capable of handling a heater.

[truk4u]

Jon will love this... I have an extension cord plugged into one of my garage plugs with an electric heater running in the bus right now. 9 degrees ambient this morning and inside the bus barn it's 21.

I've used this little heater many times in the previous bus (no kick heaters) and also in the Liberty. The reason I plugged in outside the bus is with the water heater running, fridge and this heater, I was pushing 29 amps on one leg and was concerned it would trip a breaker and cause me a freeze problem. I'm not sure of my ampherage in the barn, it's wired for 50 amp, but the electrician that did it told me I had 25 amps on each leg.

For freeze protection at home, I turn on the hot water heater and place a light bulb in the opposite side of the plumbing bay. Stays nice and toasty in there. The Liberty electric bay heater looks like a hair dryer and is making some noise, so I don't trust it when not staying in the bus.

Gary - what to you think about the ampherage? I have a 100 amp panel in the garage and 50 amp breaker for the bus.

[JIM CHALOUPKA]

Tom, I think, if you want 50A at the plug then you need a 60A breaker, min..
The distance your plug is from the service panel and the size of the wire to the plug also come into play.

Your hairdryer heater is a heat gun.

I agree with you in that your appliance load should not exceed the rating of the circuit supplying it/them.

An observation on my barn is that the inside temp of the uninsulated bldg is usually 12 deg warmer than the outside temp. I expect this to be the case until the ground under the bldg. cools due to longer spells of cold weather.

JIM

[dale farley]

I have always used small heaters in our buses. We ran two in Yellowstone for several months with no problem. I set them to 800W at night and 1500W in the early morning. When on 1500W, I just made sure they were on different legs of the electrical system. I could easily trip my GFIC if I had a heater and coffee pot on at the same time, and that was understandable. That definitely through me over the 15 amp circuit limit.

I've run one on 800W for the last two nights, (even in Florida) because it has been below freezing for a few hours each night. It obviously doesn't get that low in my building, but I just don't like it being "cold" in the bus.

[rfoster]

Where is Al Gore? Someone needs to run his a$s out and about in the cold and then he can tell us (with teeth chattering) about global warming. Bah humbug.

One below here-- warming to 30 degrees sometime this afternoon, then snow.

The bus thermometer indicated a toasty 60 degrees inside and out in the bat cave.

[Kevin Erion]

Truk,
I am no electrician but if you want 50 amps, then a 50 amp breaker is your protection, not 60. # 6 wire is code in CA for 50 amps, I think and depending on the distance you might loose a little. You should have 50 amps on both legs as long as the electrician wired you into 220, if not find a new one!

[Jon Wehrenberg]

Kevin is correct. We have been over this before, but to make it clear a campground power outlet box typically has three receptacles.

The 20 amp and 30 amp recaptacles are 20 and 30 amp at 120 volts. That is the total amperage.

The 50 amp receptacle is a misnomer. It is actually two 50 amp legs at 120 volts for a total of 100 amps at 120.

In Tom's case he could run the devices he wants and still run his electric heater off his forward or rear outlet circuits. That assumes the electrician did give him a 50 amp RV type receptacle. To verify what he has he should have a 50 amp double pole breaker in his panel for that RV receptacle. If that is the case there is no need to run the heater from another source.

I agree with the bay heater being an industrial heat gun. I also do not use it for several reasons. On my coach it is a high wattage current draw. If I needed heat I would rather use a 500 watt setting on a small cube heater. I don't like the fact it is either spewing out a lot of heat, or it is off depending on the need. I would rather have a small continuous heat source that is quieter and concentrated on keeping the big water holding tank warm. When the tank is warm it will protect the bay in even the worst temperatures.

Jim, why suggest 60 amps? Nothing is rated for that amperage, including the receptacles, the wires, or the plugs.

[truk4u]

Kevin - I had wired the whole garage myself and put a 30 amp in for RV. After getting the first bus, it was obvious I needed 50. So I hired this guy to come out and help me run 220 to the new 50 amp bus plug I had ready, cause I'm too whimpy to struggle pulling that big wire while doing a goose walk in the trusses of the garage. I gave him a call today and he apologized for telling me it's two legs of 25, when in fact it's 2 legs of 50, just like the Campgrounds. I put 400 amp in the house when I built it and a 100 amp sub panel for the garage, so I have lots of juice.

So just for fun, I loaded the ole girl up with 2 heat pumps cranking along with the water heater and 41 amps on one leg was no problem. Now I know and the heater is running off the bus.

Jon - I called it a hair dryer cause I knew Jimmy C would have a cow.:p He's probably sitting in front of the computer right now in his jammies looking at pictures of Key West and not wanting to look out his window. That Liberty heater is probably a good one, but just like you said, it's either off or on and I don't trust it while not staying in the bus.

[Kenneth Brewer]

Tom, I think, if you want 50A at the plug then you need a 60A breaker, min..
The distance your plug is from the service panel and the size of the wire to the plug also come into play.


JIM

Sorry. No. Current is the same everywhere in a loop, unless you have a current leak somewhere to ground or neutral, in which case you have other (and serious) problems. Voltage drop occurs over distance, however, and that can be a problem (addressed with a given minimum wire size). Again, if you have 50A at the panel, you have 50A at the other end of the cable unless there is a fault to ground somewhere in between. And in that event, especially, you do not want a breaker rated higher than the (system) current you will safely and normally require, within the rated limits of the system.

Thanks for listening.

[JIM KELLER]

While working on the Bus today it was sitting outside the garage with the sun shining on it. The inside temp got hot enough I had to turn on the A.C.

[JIM CHALOUPKA]

I was trying to convey without going into detail that the breaker that one usually purchases with the 50A rating is by the NEC rating only going to work at 80% of that number, or 40A. This comes from the fact that the breaker is rated in free air @ 40C to 50C degrees, and will under those circumstances handle the 50A rating, but when in practical application they are enclosed in a cabinet/box they only perform at 80%. If one wants the 50A he needs to use a breaker labeled SP (supplementary protector), which functions at 100% of its rating. These are not as easy to find.

The plug and wire as are rated for 50A and will therefore safely carry the load protected by a 60A breaker which at 80% will protect 48A.


JIM

[garyde]

I don't want to pretend I know it all but I won't exceed 50 amp breakers on #6 wire . There are certain exceptions, but is with specific connected load not general purpose. Also, in most RV parks the wiring of the pedestals are typically wired in Parrallell (2 to 4 - 50 amp Pedestals) on one 100 amp sub feed. Meaning, you don't really have 50 amp capability if 2-3 others are drawing heavy loads at the same time.

[lewpopp]

Jim, if a 50A power outlet will only give out 80%, the power would be 46A instead of 48A. There goes those percentages. It is different if you took math in Tennessee.

[lewpopp]

Jim, if a 50A power outlet will only give out 80%, the power would be 40A instead of 48A. There goes those percentages. It is different if you took math in Tennessee.

[flyu2there]

Country Coach runs all of their 110V power (outlets only) thru the coach after it goes through a GFI, believe a 15 amp GFI but it may well be a 20. There is your answer.:p

John

[Kenneth Brewer]

Jim,

Your description of the rating of circuit breakers is true. But, nevertheless you may NOT put a 60A rated breaker on a 50A rated circuit, if that is what the circuit is rated (wire sizes enter in to the situation, among other things). Fault current/short circuit study evaluations are also a factor when sizing breakers, as well as whether or not ground or neutral might be involved, or whether we are talking a line breaker or load breaker. An electrical inspector that spots something like this
will fail the inspection, industrially or commercially. Equipment in question would have to be shut down immediately.

Inspectors can and do make mistakes that help or hurt owner/operators, and I can testify on this from over 40 years experience/exposure, but the code seems pretty clear here. By the way, the code with regard to cirbuit breaker rating is hotly contested (nothing new) whenever the NEC makes a revision. Whether or not something is a code violation is often argued, even by IEEE and/or NEC contributors, but I think this is an 'easy' one.

We need to be very careful when recommending electrical protection advice. The easiest way to stay out of trouble is to stay at or below current or voltage ratings.

Now I'm done on this one.

[Jon Wehrenberg]

Jim,

The 80% is no secret. It has been discussed here on this site numerous times.

Power management is a must on these coaches, and when we are on 50 amp service, we can do pretty much anything we need to do with little concern as long as we are aware that sustained power usage in excess of 40 amps per leg (or 24 amps total, or 16 amps total, depending on power source) may trip the breakers. The answer however is not to step up the breaker size because everything, including our power cords is sized for 50 amp service.

I want the breakers at the campground power outlet to trip long before I have a fire due to overloaded wires.

[truk4u]

Great answers from the electrical dudes in our group, I'm sticking to 12/24!:cool: As a practice, I always watch the amp loads and when they push into the high 30's on any leg, I start reducing loads.

Here's another teaser.... When running on gen, if the loads get real high on one leg and voltage starts down into the teens, the other leg voltage climbs to about 130 volt. The Liberty does this and also my CC did. I talked to Powertech about this and they said that is normal. Just curious why this happens.

[jello_jeep]

Because of the lack of un-obtainium used in the current breakers, outlawed by Al Gore in the 90's, as the manufacture of it caused the current global warming in the South.


Just curious why this happens.

[JIM CHALOUPKA]

OK, Jon and Ken. I am not disputing what you have said.
You have taken my statements out of context. I was answering specific implied questions by Truck.

I said, "Tom, I think, if you want 50A at the plug then you need a 60A breaker, min.. ( that means to me that if he wants 50A at the plug with common breakers he needs a line [properly sized] and with a 60A breaker min nothing more implied )
The distance your plug is from the service panel and the size of the wire to the plug also come into play." (that means to me check it out and we can discuss it if you want [had he come back with the wire size I would have suggested that it would determine the breaker size])

Other things that were not specifically discussed were voltage drop at the plug (due to the length of the run, and total watts required at the end of the run [the plug]. These values are unknown to me and I wanted Truck to know that they have an influence on his electric circuit.


From what I read in Truck's post I got that he asked for something (from his electrician) and did not know whether he got it or not. Truck was talking about a 100A panel with a 50A breaker and 25A on each leg and 29A load, well what does he have there. I meant that he could look at his wire size and if in fact he wanted 50A at the plug he should have a 60A breaker in the service panel min. and to check the wire size to the plug. (#6 THHN insulated copper wire will handle 70A ). If he only had (#10 THHN copper wire, which is good for 40A he should not even use a 50A breaker)

#6 wire and standard 50A breaker are used for a circuit that is commonly called a 50A circuit. You do not however have a circuit that will be rated 50A for a continuous draw of 50A.

I do not know what he had, has or wants. I was only trying to offer knowledge so he could decide for himself with what I mentioned, and a little discussion, which did not happen.

I did not say he should or must do anything.

I believe nothing I have said is incorrect.

:)JIM

[truk4u]

# 6 wire and I got my answer from my Electrician as previously posted.

Thanks for helping Jimmy C, I think you need a sunny Liberty vacation!:D

[JIM CHALOUPKA]

Your right about that Thomas, but it's not happening now.

JIM :(

[Jon Wehrenberg]

Jim, just think of 20, 30 or 50 amp as a nominal value, just like 12 volt batteries are not really 12 volts.

When sizing wires and components it is still based on breaker rating. You may not be able to get 50 amps continuous through a 50 amp breaker, but you still need #6 wire.