Questions Regarding Max Amp Usage

[Steve7]

Can you do a quick test? Where the wire comes out of the breaker at the pedestal, put the clamp meter there and note the amps (with all your loads). Then put the clamp on the neutral and measure the amps and report back please.

Hi Curtis,

I could have done that yesterday when we had the panel open, but it’s too busy today to do it with the park personnel. BUT, I have a neighbor who has a clamp Meter, and I can do it myself if it’s worthwhile. Can you tell me what we’re looking for or what we’ll accomplish by doing this test so I can decide whether to do it without an employee?

Steve

[offtohavasu]

I want to see what the actual amperage is at the breaker and what is being returned on neutral

[Steve7]

I want to see what the actual amperage is at the breaker and what is being returned on neutral

Yeah, I figured that, but if it’s not what it should be, what does that tell us?

[acadiaforever]

If the neutral current is less than the hot current, it would mean that you have a leak to ground. If you can read it on the resolution of a clamp meter in the 40A range, it would be a SERIOUS leak to ground. For even small leaks to ground, your EMS should have shut you down.

[Steve7]

If the neutral current is less than the hot current, it would mean that you have a leak to ground. If you can read it on the resolution of a clamp meter in the 40A range, it would be a SERIOUS leak to ground. For even small leaks to ground, your EMS should have shut you down.

Got it Al, thanks. If I get the opportunity, I’ll check it tomorrow morning.

[offtohavasu]

Thanks Al.

[carnolddsm]

If the neutral current is less than the hot current, it would mean that you have a leak to ground. If you can read it on the resolution of a clamp meter in the 40A range, it would be a SERIOUS leak to ground. For even small leaks to ground, your EMS should have shut you down.

Not necessarily, on 50 amps the two hot legs are supposed to be 180 degrees out of phase with each other. The neutral in these systems only carries the difference in loads of each leg. Example: leg black is passing 20 amps, leg red is passing 5 amps, the current on the neutral is 15 amps (20 - 5).

The two hot legs cancelling each other allows the neutral wire to be sized the same as the hot legs. If this were not the case on a 50 amp RV cord the neutral conductor would have to be significantly larger.

The reason for saying the two hot legs are “supposed” to be 180 degrees apart is I’ve seen reports of RV parks being incorrectly wire with both hot legs in phase. This can cause a serious overloading of the neutral wiring.

[Jerryr]

Not necessarily, on 50 amps the two hot legs are supposed to be 180 degrees out of phase with each other. The neutral in these systems only carries the difference in loads of each leg. Example: leg black is passing 20 amps, leg red is passing 5 amps, the current on the neutral is 15 amps (20 - 5).

The two hot legs cancelling each other allows the neutral wire to be sized the same as the hot legs. If this were not the case on a 50 amp RV cord the neutral conductor would have to be significantly larger.

That’s true with a 50 amp 240 v service. What was asked was to measure hot current and neutral current at the pedestal 30 amp 120 v single pole breaker that supplying power to the trailer.

[offtohavasu]

If the neutral is not matching the output, that is going help to start diagnosing issues.

[carnolddsm]

That’s true with a 50 amp 240 v service. What was asked was to measure hot current and neutral current at the pedestal 30 amp 120 v single pole breaker that supplying power to the trailer.

My apology, I missed that.