Voltage Drop - NOT Park Problem

wnjj wrote:

ThruTraffic wrote:

wnjj wrote:
I think this was mentioned earlier but you need to put a decent load in the RV then measure the voltage at every possible place you can between the source and load. You’ve said the voltage is good at the pedestal and bad at the load. This means there is a resistive connection somewhere. While under load, measure the output side of the breaker the load is connected to in the RV panel. Then measure another one to eliminate the breaker and wiring to the load. Next move upstream to the feeder line, transfer switch, etc.

The problem will be between the last “good” voltage and first “bad” one.

25 amps good enough? Note my last big post. There's nothing left to test; it's all new.

Maybe I'm missing something but I saw a post with various voltage drops measured with increasing loads turned on but not one where you measured multiple places along the same circuit. Your last big post talks about replacing a bunch of stuff. Neither of those addresses my suggestion.

When you have a voltage drop between two end points, there has to be an explanation. If it's simply due to wire size/length it will continuously decrease along the way and as you say it will be normal.

If what you are experiencing is abnormal, there must be someplace causing the drop. Rather than guessing, you should measure the voltage along every specific place you can access between the supply and the load.

You're also a bit all over the place with changing shore power cords and pulling the meter when as you said, the same happens on the generator. So the problem either persists inside your RV, or it's not actually a problem at all and is normal.

Does anyone actually think I've not been measuring voltage during every test or component replacement?

NEC:
The National Electrical Code contains six Fine Print Notes to alert the Code user that equipment can have improved efficiency of operation if conductor voltage drop is taken into consideration.

1. Branch Circuits – This FPN recommends that branch circuit conductors be sized to prevent a maximum voltage drop of 3%. The maximum total voltage drop for a combination of both branch circuit and feeder should not exceed 5%. [210-19(a) FPN No. 4], Figure 2.

2. Feeders – This FPN recommends that feeder conductors be sized to prevent a maximum voltage drop of 3%. The maximum total voltage drop for a combination of both branch circuit and feeder should not exceed 5%. [215-2(d) FPN No. 2], Figure 2.

I can measure a normal voltage of 121v to to a low of 108v under a less than 25 amp load. Using 5% of 121 volts results in an acceptable loss of 6.05v or 121 down to 114.5.

Do you think 108 is normal or acceptable?

My old a/c compressor had a locked rotor current of 51 amps. Under the conditions I've described it's no wonder the the compressor died when attempting to start with a voltage that low. No way can a start capacitor overcome that for very long.


So let me ask all the "that's normal" believers who own 30amp rigs: What happens to the voltage in your RV when you throw a water heater and a microwave and a toaster at it. Do YOU loose ~10% of normal voltage?