Looking for electrical system advice

[chef john]

We went camping this past weekend for the first time in our new 5th wheel. It was a little cold outside. Ran the furnace and it seemed a little loud. My question is...if I am hooked up with 30amp can I run a small oil filled radiator. Like the $60 ?ones that you can buy anywhere. I use one in my office at home and it heats a 15' X 12' room great. Another question...if I plug an adaptor into my pig tail so I can hook up to a standard 110v heavy duty (orange cord) extension cord at home...is it alright to leave it plugged in all the time? What about lightning? What can I safely operate in the 5er with it hooked up like that? I guess I am just trying not to tax my electrical or burn the thing up. Any advice is greatly appreciated. I have found this forum to be a huge help and wealth of knowledge. Thanks to all.

 

[Ned]

If you are connected to 30A power, you can use up to 30A, whether it's an electric heater or your AC/heat pump (if you have one).  If you're using a 20A extension cord, then you're probably plugged into a 20A circuit, or even 15A (check the breaker) and can only use as much power as the circuit will allow.

 

[Bob Buchanan]

My question is...if I am hooked up with 30amp can I run a small oil filled radiator. Like the $60 ?ones that you can buy anywhere.

Yes. Some campgrounds will not allow the use of electric heaters, so be careful to read the rules on that when you check in.

Another question...if I plug an adaptor into my pig tail so I can hook up to a standard 110v heavy duty (orange cord) extension cord at home...is it alright to leave it plugged in all the time? What about lightning? What can I safely operate in the 5er with it hooked up like that?

That should be OK -- as long as the length is not excessive. You also want to check to see what amperage the house breaker is that feeds the 110 -- plus try to find one that is not used for something else. I'm hooked up that way right now and have been for several months. I'm careful when I run my air conditioner not to also run micro wave and electric water heater.

 

[BruceinFL]

Yes. Some campgrounds will not allow the use of electric heaters, so be careful to read the rules on that when you check in.

How would they know, Bob.

 

[Ned]

How would they know, Bob.

That's not the point, is it?  They may not know but you would.

 

[John From Detroit]

I have been in campgrounds where they said "no electric heaters" (I'm thinking the Las Vegas KOA was one but I'm not sure)

However. due to the way the furnace works in my rig, we found it nice to have an electric heater in the back.

I'm paying for the power no matter if I use it or not, so I'm going to use it.

A 30 amp power supply will run TWO 1500 watt electric heaters (The normal size) however this leaves very little over for things like keeping your battery charged or microwaving water into coffee with your Melitta one-cup microwave coffee maker (That takes 10 -15 amps)  However if your heater has a HI/LO setting then it can run one on high and one on low very well

Just make sure each heater is on a seperate breaker in-house (I have one in my rig now running off the washer/dryer outlet, since I don't have a washer/dryer)

 

[Ned]

No, you're not paying for the power if you don't use it.  Those parks that say "no electric heaters" usually have an extra charge for A/C, electric heaters, etc.  If you want to use them, then pay for them.  The camping fee in those cases is based on the average electricity usage without those power hungry appliances.

 

[Carl L]

Another question...if I plug an adaptor into my pig tail so I can hook up to a standard 110v heavy duty (orange cord) extension cord at home...is it alright to leave it plugged in all the time? What about lightning? What can I safely operate in the 5er with it hooked up like that? I guess I am just trying not to tax my electrical or burn the thing up

That depends on what else is on that circuit.  Most older household circuits are protected with 15 amp breakers -- and given the wiring used, with good reason.  If you have appliances on that circuit you are going to run into load load issues when they cycle up.

I have a  dedicated 20 amp circuit in my garage.  I had it installed during a remodeling.  Since there is nothing else on the circuit and it is 20amp I can run my trailer even the single 13,500 btu A/C.  However, when I used a good 15amp 50 ft extension, I was getting overheating of the cord at the connection.  Never I good sign.  I switched to a 30amp extension, wired in a 30amp RV receptacle, and wired a 20 amp switch ahead of it.  Since a trailer always plugs in with a significant load, a switch is needed to prevent arcing and burning your plug blades.

 

[Karl]

if I am hooked up with 30amp can I run a small oil filled radiator. Like the $60  ones that you can buy anywhere. I use one in my office at home and it heats a 15' X 12' room great.

Just a couple comments on that - Those oil-filled radiators work fine for individual rooms where air convection distributes the warm air more or less evenly throughout the room. The typical motor home is not a 15' x 12' room; it's basically a long tunnel, and convection itself may not distribute the heat as you would want it to. Most of us supplement our regular furnaces with those small ceramic or 'milkhouse' heaters with a fan to make sure the heat goes where we want it. I think that would be a better choice as long as the sound of the fan is not too great; some are much quieter than others. Also remember that you won't have the 4"-6" insulation in a MH that you have in a stick house, so many of us prefer to use a small heater in the bedroom area at night (letting the rest of the MH become colder), and then using the furnace in the morning to heat up the rest of the MH as necessary. 

I prefer not to get into the moral/ethical question of using an electric heater or a/c when you're not allowed to do so without paying a separate charge. If enough people do that, eventually everyone will pay for it by increased daily fees. Let your conscience guide you.

 

[John From Detroit]

Learned sometihng today Carl, thanks.

I too wired a 20 amp line and breaker to a 30 amp RV outlet next to where I park the rig

 

[janpaul]

Why would you wire a 20 amp circuit to feed a 30 amp line? If you load the 30 amp line to it's capacity you will overload the 20 amp circuit feeding it and trip the breaker.  A residential circuit breaker works on an inverse time curve, the higher the current goes shorter the trip time. Two 1500 watt heaters at 120 volt will draw approx. 25 amps which is too much for a single 20 amp circuit. Most circuits are designed to have an allowable percentage figured in depending on whether or not the load is continuous or non-continuous(on for longer than three hours). A typical 20 amp circuit should not be loaded greater than 16 amps (125% rule per NEC) unless everything in the curcuit is listed to be run continuous under full load rating.

 

[Carl L]

Why would you wire a 20 amp circuit to feed a 30 amp line? If you load the 30 amp line to it's capacity you will overload the 20 amp circuit feeding it and trip the breaker.

You missed the point.  I had a 20amp dedicated circuit available.  The set up was at the home base, and was not a live-in siting.  The load was not a full 30amps by a long shot being largely just battery charging and fridge operation.  I found by experiment with a line voltmeter that the use of the single A/C would not cause excessive voltage drop.  However, that was just a trial use, not a typical load.  And of course the microwave is never used at home base. 

The use of the 50 foot 16 ga extension cord introduced a bit too much resistance so I went to a 30amp rated 15 foot extension and extended the trailer's 30 amp power cord.  That works just fine with no signed of excessive resistance.

If I were wiring in a house circuit purposely for a live-in trailer, I would certainly have it wired for 30 or 50 amps as indicated.  If I were using the trailer as a living unit, I would certainly have special wiring done.  For simple home basing or storage, with only fridge, charger, and lighting as a potential load, dedicated 20 amps works just fine.

 

[chef john]

Thank you for all the great advice. Currently I have a 50' 15 amp cord connected to the trailer. Nothing is running in it except the lights when we go in. I have been told that keeping the heater set at 50 degrees during the winter is a good thing. I live in South Carolina so it doesn't get really cold down here. And if it does it doesn't stay cold for long. I think I need to shorten my extension cord, and I'll be alright. Let me know what ya'll think. I think my next line of questioning will be about winterizing. Oh, I did notice on my pigtail that one of the blades has corrosion on it, it that normal or a sign of something wrong? If all I have running in my 5ver is the lights when we go in and the heater set at 50degrees will I be OK?

 

[Carl L]

If the corrosion is black it is probably residue from arcing at plug in.  Putting a switch in the ciruit will cure that.  Otherwise just clean it off.  Your power is going to be running your charger for your batteries.  They in turn will run your lights and furnace.

 

[janpaul]

Have you guys ever seen Meltric brand plugs. They are rated for load breaking and even as a motor disconnecting means. Very nice devices but the price tag usuallty associated with nicer things also applies.
http://www.meltric.com/?gclid=CLi1ntCNu4gCFUo7Ggod5QFizw

 

[Gottasmilealot]

The best thing to do is to turn on anything that you would want to run while your rig is parked, and measure it with an amp-probe. ?That will give you the total amperage draw, and you can then size your feed accordingly, based on the amperage plus line loss if the cord is long.

When at home, I use an adapter on the 30 amp cord so I can plug it in to a wall outlet in my basement for that purpose. ?I can run anything except the AC unit; the batteries stay charged, and I have use of the lights if I want to work on anything. ?I can turn on the refrigerator so it's cold for departure. ?I'm really not too restricted. Most of the dometic refrigerators draw maybe 2.5-3 amps. ?Information in this regard is on Dometic's website if you want to look up your model in particular.

With regard to portable oil filled heaters, for the sake of discussion, I happen to have an oil fired radiator at the house that has selectable wattage (600, 900, or 1500 watts). ?To figure out the amperage from the known wattage, divide the wattage by the voltage. ?600 watts draws 5 amps (600/120), 900 watts draws 7.5 amps (900/120), and 1500 watts draws 12.5 amps (1500/120). So, with a 15 amp line, you can run the heater, but not much else. ?It would be a better situation to just run it on the lowest setting if you must use it, but realize that it may never bring the rig up to temperature and may run all the time, even with the thermostat. That can't be good for your electric bill, and the use of a portable heater bring other safety considerations to mind, so be careful if you use one. As a comparison, some of the hair dryers will consume 1500 watts. A ceramic heater or other appliance should have their amperage on a plate or label attached to the unit. If you don't have the means to use an amp-probe, just add up the wattages of the refrigerator, furnace, lights, etc., and divide by 120 (as in 120 volts) to get you close.

I don't use a heater in the motorhome when it's just parked, no need to, as it's winterized. ?No use attracting field mice. ?If I want to work in it for a few hours, I just open the gas valve and turn on the thermostat.

Good luck!

 

[Tom]

To figure out the amperage from the known wattage, divide the amps by the voltage.

A slip of the keyboard there. We knew that you meant divide the watts by the voltage.

 

[chef john]

Thanks again for the wisdom. Are the ceramic heaters the most widely used form of alternative heat for RVers? I have a friend at work that says he never uses his furnace, he uses cermaic heaters. Then Karl says he uses cermaic heaters. What about others. I like the oil filled heaters because there is no fan noise, but safety and keeping my electrical system functioning are my number one priorities.

 

[Gottasmilealot]

A slip of the keyboard there. We knew that you meant divide the watts by the voltage.

Absolutely right.  Good catch. I corrected the post. Thanks!

 

[Tom]

I corrected the post.

A man after my own heart. Whenever I or someone else discovers an error in one of my posts, I just have to go back and fix it. I have to fix a number of my posts for this reason