Voltage problem revisited

Topic: Voltage problem revisited (Read 2889 times) previous topic - next topic

Voltage problem revisited

November 19, 2019, 11:30:28 pm

I'm tired, it's late and I will peruse this tomorrow.
When I hooked up my power cord to my 50 amp Progressive Industries ..EMS, it read each leg at 118. This is a brand new service pedestal with no known issues. Went into the coach and NOTHING shows on my display??? I needed to keep batteries charged so I checked the adjacent 30 amp outlets on the same pedestal, put on my pigtail and plugged into it for the night. It lite up the display now showing 113 volts each leg. The POSSIBILITY exists that I miss wired the new plug I put on in Texas How do I proceed testing continuity tomorrow.? Do I test at the transfer switch under the bed? I don' t understand how I get no reading at 50 amp but I do at the 30 amp outlet. BTW...this is a standard house outlet, not the 30 amp we normally see in RV parks.
Any ideas? Barry? Thanks

Re: Voltage problem revisited

Reply #1 – November 20, 2019, 12:37:04 am

Glenn, sounds like your EMS is portable, which is fine. I assume coach does the same when plugged in without EMS.

The 50amp plug has two hot prongs, one neutral (center), one ground (round). The 2 hots are powered from separately from the pedestal. The 50 to 30 to 20 amp pigtails take the single hot from the 20 or 30 amp outlet and sends it to both 50 amp hot prongs.

BTW, the household outlet is 20 or 15 amp, not 30 amp.

Seems that if pigtails work, and the pedestal is ok, both should work the same.

One way to test with meter is to partially connect 50 amp male plug so some of the brass prongs show. Put meter on the energized visible prongs. Be careful they are hot.
Hot to hot is zero with pigtalis, 240 volts with pedestal.
One hot to neutral is always 120 volts.
Other hot to neutral is always 120 volts.
Neutral to ground is zero volts.
Each hot to ground is 120 volts.

BTW, 120 volts means anything between 109 & 129. 240 volts means anything between double the 120 volts. Approximate is ok as long as it is close.

If it works sometime and not others, jiggle plug for loose attached copper connection.

Let us know what you find.

What are you looking at when you say nothing shows on my display, what display.

Barry

Re: Voltage problem revisited

Reply #2 – November 20, 2019, 06:45:42 am

Your EMS may have a couple minute delay before it lets power into the coach. Make sure you're allowing for this when checking inside for power.

Re: Voltage problem revisited

Reply #3 – November 20, 2019, 08:47:29 am

I think folivier meant ATS. My OEM ATS sometimes takes a couple minutes (seems like a half hour sometimes) to connect with a clunk. The portable EMS PT-50X does several continuity tests and will show voltage, Hz, and amps, and an "E" value. If you don't see "E-0", the EMS will block all power. The EMS also has a time delay if it encountered a temporary voltage issue. That delay is 2 minutes and 16 seconds. So it may take around 5 minutes to get safe power to the coach. Try plugging in 50 amp and wait a few. Just my ez button. Woody.

Re: Voltage problem revisited

Reply #4 – November 20, 2019, 08:57:07 am

Yes, if you are safe working around 120/240 VAC, open the ATS. If two open the one with generator and shore IN and OUT to main breaker panel (the one to the main breaker box is short and easy to trace).

Check for power IN and OUT

On 50 amp shore power:
Black to white= 120 VAC
Red to white= 120 VAC
Black to green= 120 VAC
Red to green= 120 VAC
Green to white= 0 VAC
Red to black= 240 VAC

On 30 amps-- all the same except red to black= 0 VAC

If you don't get those readings on the IN side, work back toward shore power cord until you find the culprit.

On the shore power cord:
Two outer straights= hot
Center straight= neutral
Center round= ground

Re: Voltage problem revisited

Reply #5 – November 20, 2019, 09:26:02 am

Sort of a side bar ... Could one take 30 amps from two power posts to a Y connection with a 50 amp connection at the end of the Y? Hot from both 30 amp combined to the 2 50 amp hot blades? Hot from each 30 amp to one or the other 50 am hot blade? Can you buy something like a 2-30 amp to 50 amp pigtail?

Re: Voltage problem revisited

Reply #6 – November 20, 2019, 09:31:57 am

Quote from: Roger & Susan in Home2 – November 20, 2019, 09:26:02 am

Sort of a side bar ... Could one take 30 amps from two power posts to a Y connection with a 50 amp connection at the end of the Y? Hot from both 30 amp combined to the 2 50 amp hot blades? Hot from each 30 amp to one or the other 50 am hot blade? Can you buy something like a 2-30 amp to 50 amp pigtail?

Lots of "IFF's" here.

At most that would give you a total of 60 amps vs 100 for 50 amp shore power.

Are both hots on the same "Phase"? If so it would be possible to overload the neutral, as the neutral is only designed to carry the DIFFERENCE between draw on L1 and L2.

And, most shore power pedestals have one 50, one 30 and one 15/20. With code being that the 15/20 be in a GFI which would trip with this adapter.

So, for 90% of RV owners, I would strongly suggest against it.

For those with a strong electrical background/knowledge-- MAYBE.

Re: Voltage problem revisited

Reply #7 – November 20, 2019, 09:46:27 am

Brett Wolfe wrote "Yes, if you are safe working around 120/240 VAC, open the ATS. If two open the one with generator and shore IN and OUT to main breaker panel (the one to the main breaker box is short and easy to trace)."

Safe means proper technique, and it's not that complicated.

Wear rubber soled shoes.

Put an alligator clip on your black or negative test lead.

Put your off hand into your pocket.

Clip the black lead to your common rail.

Probe with your good hand and keep your off hand in your pocket.

Art

Re: Voltage problem revisited

Reply #8 – November 20, 2019, 10:25:31 am

Glenn,

Here is a good site on how to wire your 50 amp RV plug. How To Wire A 50 Amp RV Plug: Here Are 5 Quick And Easy Steps . Nothing like a picture to say a thousand words. Why not ask the RV park for their electrical person to give you a hand?

Pierce

Re: Voltage problem revisited

Reply #9 – November 20, 2019, 10:40:24 am

Thanks to all. I plugged in PI EMS and it read all is good...118 each leg and EO. Went inside...display showed nothing. Disconnected EMS and plugged in direct. One leg low the other high... just like what happened in Texas when the round ground broke off the main power line. Looks like I will be rewiring plug. Probably a loose ground. You guys are the best

Re: Voltage problem revisited

Reply #10 – November 20, 2019, 10:52:41 am

The wiring looks ok to me
I am going to plug it in "open" like this so I can multimeter all connections
YES... I will be super careful

Re: Voltage problem revisited

Reply #11 – November 20, 2019, 11:08:53 am

A couple of diagrams:

https://www.youtube.com/watch?v=9hmuUBWKwGo

https://www.youtube.com/watch?v=GoOR2AJGjOI

Re: Voltage problem revisited

Reply #12 – November 20, 2019, 12:01:00 pm

No apparent problem at the pole but I read 107 and 139 inside
The question is WHY? and where do I look for the problem?

Re: Voltage problem revisited

Reply #13 – November 20, 2019, 12:13:27 pm

Quote from: GleamB – November 20, 2019, 12:01:00 pm

No apparent problem at the pole but I read 107 and 139 inside
The question is WHY? and where do I look for the problem?

Don't believe the factory monitor, read voltages at the 2 different outlet circuits.

Re: Voltage problem revisited

Reply #14 – November 20, 2019, 12:15:42 pm

Don't believe the factory monitor, read voltages at the 2 different outlet circuits.
[/quote]

Outlet circuits?
Where do I test them?

Re: Voltage problem revisited

Reply #15 – November 20, 2019, 12:19:29 pm

Use one of the outlets around the sink area, doesn't matter which one and check one on the opposite side, not knowing your floor plan find one near the front. My monitor gives screwy numbers sometimes and the voltages are ok.

Re: Voltage problem revisited

Reply #16 – November 20, 2019, 12:28:03 pm

Problem is on the neutral wire. Problem could be in cord reel if you have one or transfer switch. Are you using your EMS and it is showing good voltage but the coach is not?

Be careful you can smoke all of your electric items on the high voltage side.

Re: Voltage problem revisited

Reply #17 – November 20, 2019, 12:51:05 pm

Quote from: GleamB – November 20, 2019, 10:40:24 am

Thanks to all. I plugged in PI EMS and it read all is good...118 each leg and EO. Went inside...display showed nothing. Disconnected EMS and plugged in direct. One leg low the other high... just like what happened in Texas when the round ground broke off the main power line. Looks like I will be rewiring plug. Probably a loose ground. You guys are the best

Maybe an illusion, but looks like the black hot is not making a good connection.

Re: Voltage problem revisited

Reply #18 – November 20, 2019, 01:47:13 pm

Agree with Brett...in the picture of your open 50a plug, your black connection looks marginal. Also looks like your green ground wire might have been pressed against the neutral lug when you screwed the case together...sufficiently to possibly make connection ground to neutral...not good. I'd rewire it just in case. Agree too that the Foretravel monitor is not state of the art. It's just plugged into an dual outlet behind the panel. Better than nothing I guess, but the Progressive portable is SOA. Woody.

Re: Voltage problem revisited

Reply #19 – November 20, 2019, 01:57:46 pm

PI EMS does show an open ground
I will redo plug and try again

Re: Voltage problem revisited

Reply #20 – November 20, 2019, 02:16:49 pm

Then the problem is between your power plug and the breaker box in your coach.

Re: Voltage problem revisited

Reply #21 – November 20, 2019, 03:51:16 pm

Quote from: Pyolet – November 20, 2019, 01:47:13 pm

Agree with Brett...in the picture of your open 50a plug, your black connection looks marginal. Also looks like your green ground wire might have been pressed against the neutral lug when you screwed the case together

Also can't see the neutral in the picture provided, but hopefully it looks better than the black connection.

Re: Voltage problem revisited

Reply #22 – November 20, 2019, 04:10:59 pm

Everything seems to be okay running through the EMS. I want to thank you all, once again, for taking interest in my problem. I actually used a multimeter on most of the outlets in the coach and all were reading good. I will keep an eye out fo any irregularities.

Re: Voltage problem revisited

Reply #23 – November 20, 2019, 05:15:47 pm

Oops
Premature. All is okay.........UNTIL we turned on the electric switch for the Aqua Hot,,, Then we get 136. and. 110.!!
We HAVE to be able to use the electric switch, as we are too close to our neighbors, and they wouldn't appreciate the diesel smell.
I have a call into Rudy, so I KNOW everything will be ok. Without AH it's 120 ish.

Re: Voltage problem revisited

Reply #24 – November 20, 2019, 05:19:11 pm

That still suggests that someplace the neutral conductor is not making good contact, wire broken, if cord reel may be poor contactor in it, etc.

You need to get this fixed before it "lets the smoke out" of some of your electronics from extreme low/high voltage.

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