Amps For Dummies!!! (Like Me)

[Gooselover]

I think I may know the answer to this, but just want to help educate myself in case I don't quite understand.

If you are plugged into a 30 amp power source - does that mean you cannot draw more than 30 amps without tripping a breaker?

So, let's say I have a fireplace going which draws 11.7 amps max, the refrigerator which let's say draws 10 amps, and a microwave going that draws 9 amps - then I am at my limit on amps from a 30 amp plug?

[pianotuna]

Hi Tom,

There is an improper way to modify a pedestal using the wires for energizing both the 30 amp and 20 amp outlets. In that case, it is possible to overload the feed line coming to the pedestal and the breakers would not trip.


I know it is illegal to wire in this manner where I live--so the scenario of an overloaded pedestal is not going to happen, when I'm in a campground within Saskatchewan.

[wildtoad]

Trail-Mate wrote:
If a 30 amp only pedestal (not 50 amp) 30 amp is the max load for the entire pedestal the 30 amp plug and the 20 amp.

Is this true even if they have their own breaker??

[john_bet]

j2catfish wrote:
X2 - finally someone has stated the design (correct) amp draw. Always plan for the 80% and you will probably have no problems with circuit breakers popping. If this is not sufficient, about the only real solution is to re-engineer the main power to the coach for 50 amp service.
Just my take, your opinion may vary but check with a good/experienced electrician.
Catfish

pianotuna wrote:
Hi,

The continuous duty is 80% of 30 amps. i.e. you really only have 24 amps available for constant use.

The fridge draws more like 4 amps not ten.

For brief periods of time (read a second or two) drawing more than what the breaker is rated at will rather rarely trip it.

X-3 and the 80% is for any size breaker even super big ones in industrial use.

[Gooselover]

Thanks everyone for clarifying this for me! I guess my thinking pattern was correct!

[Veebyes]

Pretty easy to tell if you are at overload or very close to it. Go out & feel the power cord at the plug & feel the circuit breaker. If they are warm or hot turn something that draws big power off. Start with things that create heat such as the water heater, the hair drier, the coffee maker, toaster, you get the idea.

[Trail-Mate]

You can overheat the pedestal . Plug into 30 amp and run it close or at max power for the 30, then plug in a 1500 watt heater in the 20 amp plug in the same pedestal. None of the breakers will trip but you can overheat the pedestal and could cause a fire. If a 30 amp only pedestal (not 50 amp) 30 amp is the max load for the entire pedestal the 30 amp plug and the 20 amp. I encountered this last year when I was on a 30 amp just getting set for winter. The pedestal got very hot and could smell wiring. Breakers would not trip because each one was not over the limit for their load, but together it was overloaded. From my encounter with this. on a 30 amp pedestal, I would run a 1500 watt electric from inside the camper( 30 amp ) and no more that a 750 watt on the extension cord to 20 amp outlets.

[RoyB]

We like to use a couple of electric heaters verses the propane furnace and most of the time can run an separate extension cord out to the CG pedestal and plug into their 20AMP service plug just for the electric heaters. This has its own circuit breaker and does not take away from the 30AMP circuit breaker.

Roy Ken

[j2catfish]

X2 - finally someone has stated the design (correct) amp draw. Always plan for the 80% and you will probably have no problems with circuit breakers popping. If this is not sufficient, about the only real solution is to re-engineer the main power to the coach for 50 amp service.
Just my take, your opinion may vary but check with a good/experienced electrician.
Catfish

pianotuna wrote:
Hi,

The continuous duty is 80% of 30 amps. i.e. you really only have 24 amps available for constant use.

The fridge draws more like 4 amps not ten.

For brief periods of time (read a second or two) drawing more than what the breaker is rated at will rather rarely trip it.

[pianotuna]

Hi,

The continuous duty is 80% of 30 amps. i.e. you really only have 24 amps available for constant use.

The fridge draws more like 4 amps not ten.

For brief periods of time (read a second or two) drawing more than what the breaker is rated at will rather rarely trip it.

[Golden_HVAC]

Hi,

THe circuit breaker can go over it's limit for a short time if it is a small amount over the 30 amp limit. So it might hold exactly 30.2 amps all night long. Or trip at 31 amps after about 1 minute. Instant trip will happen at 45 amps or more, while it should trip within 3 seconds when between 35 and 45 amps.

Anyway if you want to make sure it will not trip, keep amperage below 25 amps, and you will not be overloading the circuit breaker or the wiring, and probably will not overheat the plug or receptacle. However I have overheated a bad receptacle at only 16 amps draw before, with a 13 volt drop across the receptacle at that point.

So basically keep track of the amperage of the items you plan to run, and you can keep it below 30 amps pretty easy.

Remember that the converter/charger will always be on unless you can turn it off. So it can use 1-2 amps most of the time, or up to 4 amps when the batteries are close to dead.

A TV set is about 1 amp, but the flat screens can be less.

Your refrigerator is only 3.5 amps - if it is a propane / electric one. Might be 3-5 amps if it is a 120 volt compressor type such as used at home, with an additional 3 amps during ice harvest.

Your electric heater can be 12.5 amps on high heat, but you can reduce that to about 8 amps on the low setting.

Electric water heaters can use between 3 and 8 amps, depending on model.

Electric blankets are about 1 amp.

What is surprising is toasters are 8-10 amps.

Hair Dryers up to 12.5 amps

Air conditioners can use 12 amps on a cooler day, and up to about 14 amps when it is over 100F outside. However their surge amperage when restarting can be 35 amps for about 3 seconds - that is why the 30 amp breakers do not trip at exactly 30 amps, but will hold at 55 amps for a couple of seconds.

Fred.

[wandering1]

Sounds like you need a calculator??????

[Yaj]

You are actually .7 amps aver the breaker limit and it will probably trip. Breakers don't like to be operated at their limit.

[newman_fulltime]

Repeat this 30amps is 30amps no more you connot get more cheat it outsmart it it knows.

[downtheroad]

Pretty much.