Crack Down on 50 Amp Rigs Using 30 Amp Sites
I don't know how long this has been going on but I learned today that some RV parks including the Washington/Pittsbugh KOA I had booked has a policy that if your rig has 50 amp service, you can't use ...
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Actually, I'm surprised that no one responding to this thread had mentioned Ohm's law which is very alive and well with electrical current draw. It's related to RV campground electrical issues in that the resistance created by an increase in amp draw lowers the voltage delivered to the power supply circuit. MrWizard kind of eluded to this in a post stating that a 200 amp breaker box will not supply 30 amps to 7 30 amp draw users. That would require 350 amps no matter how you cut the cheese.
As the resistance goes up with amperage increases, the voltage supplied decreases unless the amperage capability supplied on the leg current supply can deliver full 117 AC at the full load pulled from it thru it's receptacle outlets. The voltage will drop until the leg breaker trips! A 200 amp breaker will not supply 350 amps without tripping no way no how!
Want to see this for yourself? Plug you 30 amp pigtail in and read the volts on a meter and then turn on your A/C and watch the voltage drop. Also perhaps you might have noticed that extension cords and/or the end connections get warm to hot when getting close to the rated amp capacity when connected for a while but will stay cool when only at say 1/2 the rated amp capacity.
In both our RV's I have installed LED digital meters which are very cheap to purchase online form like Amazon etc for both AC and DC. The DC meter requires going thru a shunt. The meters give a constant readout of the watts, amps, volts, being consumed and an accumulative of KwH used over a desired time selected all in the digital display at the same time. A Kill-A-Watt unit will give the same but only for the selected function one at a time for an individual plugged in device on AC only. Thus, it's a portable meter vs built in constantly monitoring meters.
An electrician knows and we have seen over and over that when you first turn on an A/C roof air unit, such as a 13500 A/C unit in your RV, it will be drawing about 1300 watts after about one minute. However, after being on for an hour or more without touching the settings it will be drawing in the neighborhood of 1700 to 1900 watts depending on the outside temperature and ambient humidity. Who only runs an A/C for only one minute? Ohm's law at work as electrical resistance creates heat in the wiring and increases the resistance dropping the voltage and thus requires a higher and higher amperage draw to maintain the same function over time.
Yes, I am a retired engineer and an longtime engineering business owner and do understand much of electricals but my main discipline was automotive design and mechanical engineering as was the company I owned and ran for decades before selling and retiring.
Some RV'ers are wise and do pay attention to the amps they are drawing but that is not the norm until the breaker trips and then they usually just drop their use low enough to stay just below breaker tripping. Seen it constantly in our 53 years of RV'ing!
As the resistance goes up with amperage increases, the voltage supplied decreases unless the amperage capability supplied on the leg current supply can deliver full 117 AC at the full load pulled from it thru it's receptacle outlets. The voltage will drop until the leg breaker trips! A 200 amp breaker will not supply 350 amps without tripping no way no how!
Want to see this for yourself? Plug you 30 amp pigtail in and read the volts on a meter and then turn on your A/C and watch the voltage drop. Also perhaps you might have noticed that extension cords and/or the end connections get warm to hot when getting close to the rated amp capacity when connected for a while but will stay cool when only at say 1/2 the rated amp capacity.
In both our RV's I have installed LED digital meters which are very cheap to purchase online form like Amazon etc for both AC and DC. The DC meter requires going thru a shunt. The meters give a constant readout of the watts, amps, volts, being consumed and an accumulative of KwH used over a desired time selected all in the digital display at the same time. A Kill-A-Watt unit will give the same but only for the selected function one at a time for an individual plugged in device on AC only. Thus, it's a portable meter vs built in constantly monitoring meters.
An electrician knows and we have seen over and over that when you first turn on an A/C roof air unit, such as a 13500 A/C unit in your RV, it will be drawing about 1300 watts after about one minute. However, after being on for an hour or more without touching the settings it will be drawing in the neighborhood of 1700 to 1900 watts depending on the outside temperature and ambient humidity. Who only runs an A/C for only one minute? Ohm's law at work as electrical resistance creates heat in the wiring and increases the resistance dropping the voltage and thus requires a higher and higher amperage draw to maintain the same function over time.
Yes, I am a retired engineer and an longtime engineering business owner and do understand much of electricals but my main discipline was automotive design and mechanical engineering as was the company I owned and ran for decades before selling and retiring.
Some RV'ers are wise and do pay attention to the amps they are drawing but that is not the norm until the breaker trips and then they usually just drop their use low enough to stay just below breaker tripping. Seen it constantly in our 53 years of RV'ing!
