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Topic: Hughes Power Watchdog EMS indicating no neutral (Read 3981 times) previous topic - next topic

Hughes Power Watchdog EMS indicating no neutral

I installed a Hughes Power Watchdog EMS in my '98 U295 last year. Hardwired in to monitor power from both shore power and the Power Tech 10kw generator, it's been functioning fine on both sources.
Recently though I noticed that when running on generator power, the red LED error light on the face of the EMS is illuminated. The instruction manual says "This LED indicates there is no neutral connection in the park". It also says that if there is no neutral, the EMS will not allow power to flow into the RV, and yet power is flowing and all electrical devices are functioning normally.
I called Hughes and they told me the same thing - if the LED is lit because there is no neutral then no power should be getting through to the RV. But it is. How can I test to see whether there is a problem with the coach wiring?

Re: Hughes Power Watchdog EMS indicating no neutral

Reply #1 –
First be careful. Electrical shock can kill.  If you do not have a clue what you are doing, leave this up to someone that does.

Locate the breaker box., which I think is under the front of the bed.  Remove cover.  You should be able to see Some big #6 or so wires coming into the panel. You should also see some bars located to the side, or bottom that have white wires attached.  That is the neutral bar.  There will also be a bar where either green or bar copper wires are attached.  That is the ground bar.  Now take a voltage tester and verify it works by taking the terminals and plugin into an outlet in your home that you know it works.  Sometime you have go and verify you have the meter on the correct setting.  If you are getting 120 or somewhere close to to that then you are ready to test the panel.   

With generator running and seeing that you have power in coach such as AC fan running You are going to test between the big black and big red wires.  If on generator you probably will get a zero or so reading. This is because your generator only puts out 120V. If on shore power and connected to 50 amp 120/240v outlet you should get 240 volts or somewhere close to that.

Test between the big black and the neutral bar  You should get 120 volts
Test between the big Red and the neutral bar  You should get 120 volts
Test between the big black and the ground bar  You should get 120 volts
Test between the big Red and the ground bar  You should get 120 volts
Test between the neutral and the ground bar  You should get 0 volts

If all of your tests show what I have above then everything is correct

Re: Hughes Power Watchdog EMS indicating no neutral

Reply #2 –
Can't help with your Watchdog anomaly, but wanted to share our finding that on some problem situations that the Hughes hardwired Watchdog finds, it may still be ok to let voltage flow, like little under or over voltage.

No reason to not have shore power during issues that are otherwise understood.

Watchdog hardwired does not have the ability to bypass the device.

Hardwired Progressive Industries EMS does have a bypass switch that we have used a couple of times.

Hardwired devices need the ability to bypass because they cannot be easily removed like a portable campground pedestal EMS style.

Re: Hughes Power Watchdog EMS indicating no neutral

Reply #3 –
I've become somewhat skeptical of my Hughes 50A Autoformer giving me the same information.  I have been to parks where when plugged in to the post, it says there is a neutral issue, but then if I plug in the coach, the neutral issue light goes out.  This unit is also supposed to boost power by 10% if low voltage is found, but I've seen it bump 10% even when the incoming voltage is good, which makes the power going out to the coach too high.

Mine has been back 3 times for warranty, once for the neutral issue, once for boosting on line 1 when it wasn't needed and once for boosting on line 2 when it wasn't needed.  At last use, it had the neutral issue again. 

Re: Hughes Power Watchdog EMS indicating no neutral

Reply #4 –
Attached is my home made Autoformer voltage chart.  Yes, some boost voltages could be considered too high.

We NEVER leave Autoformer inline, and only bring it out when it is needed.  Store it in locked bay with 50-amp extension cord from bay to campground pedestal when needed.

Why wear it out this expensive unit when it is not needed?  Save it for those very few times when needed, usually high temps in older or very busy campground.  It is saved our campground stays during high temps.

BTW, freight cost to ship back this very heavy device for warranty must be out of sight


Re: Hughes Power Watchdog EMS indicating no neutral

Reply #5 –
Quote from: turbojack –

With generator running and seeing that you have power in coach such as AC fan running You are going to test between the big black and big red wires.  If on generator you probably will get a zero or so reading. This is because your generator only puts out 120V. If on shore power and connected to 50 amp 120/240v outlet you should get 240 volts or somewhere close to that.

Test between the big black and the neutral bar  You should get 120 volts
Test between the big Red and the neutral bar  You should get 120 volts
Test between the big black and the ground bar  You should get 120 volts
Test between the big Red and the ground bar  You should get 120 volts
Test between the neutral and the ground bar  You should get 0 volts
If all of your tests show what I have above then everything is correct

I ran all these tests yesterday. All checked out good. 120v between black & neutral, black & ground, red & neutral, red & ground. Zero volts neutral to ground, and 240 checking black to red (my generator puts out 240v and not 120. Modification by previous owner added a 50A 240V outlet in the generator compartment.)

I realized when doing this testing that while I initially stated the EMS error light is on only when running on generator power, but that's probably not the case. At home I don't have 240v shore power, only 120. When connected to the 120 the error light is not illuminated, but I'll bet it is when connected to 240 shore power, as I first noticed the error light when plugged into a KOA campground last fall.

Hughes has already sent me a replacement EMS, but it's a PIA to install so I'd rather not do it if everything checks out fine and is safe.

Re: Hughes Power Watchdog EMS indicating no neutral

Reply #6 –

One more thing to check.  If you have a continuity or ohm meter.  I have seen some equipment check and make sure there is continuity between the neutral and ground and will send an error message if it does not see continuity.  This test can destroy your meter if there is a voltage difference between the neutral and ground bars.  Since you said there is NO voltage you should be OK doing this test.

Do this test, unplugged from shore power and generator off, 
Check between the neutral and ground bar .  You should have 0 ohms or no continuity.
This test checked and made sure that the neutral and ground are not connected anywhere in your coach.
It is possible that this test will not test correctly if your generator is priority in the transfer switch since at the generator the ground and neutral should be connected. 

 Now try the test plugged in at your home.
Check between the neutral and ground bar .  You should have XX ohms or continuity. 
This test verifies that the neutral and the ground are connected together back at your home.  The only place the  neutral and the ground are to be tied together is at your homes main breaker box.

Now try the test generator running.
Check between the neutral and ground bar .  You should have XX ohms or continuity. 
This test verifies that the neutral and the ground are connected together back at the generator (which is good)

Re: Hughes Power Watchdog EMS indicating no neutral

Reply #7 –
Quote from: turbojack –
One more thing to check.  If you have a continuity or ohm meter.  I have seen some equipment check and make sure there is continuity between the neutral and ground and will send an error message if it does not see continuity.  This test can destroy your meter if there is a voltage difference between the neutral and ground bars.  Since you said there is NO voltage you should be OK doing this test.

Do this test, unplugged from shore power and generator off, 
Check between the neutral and ground bar .  You should have 0 ohms or no continuity.
This test checked and made sure that the neutral and ground are not connected anywhere in your coach.
It is possible that this test will not test correctly if your generator is priority in the transfer switch since at the generator the ground and neutral should be connected. 

 Now try the test plugged in at your home.
Check between the neutral and ground bar .  You should have XX ohms or continuity. 
This test verifies that the neutral and the ground are connected together back at your home.  The only place the  neutral and the ground are to be tied together is at your homes main breaker box.

Now try the test generator running.
Check between the neutral and ground bar .  You should have XX ohms or continuity. 
This test verifies that the neutral and the ground are connected together back at the generator (which is good)

I'm testing both in the breaker box as well as inside the transfer switch (see photo).
With no shore power, no generator power:
- In the breaker box, NO continuity neutral to ground.
- Transfer switch, shore power input: NO continuity neutral to ground.
- Transfer switch, generator input: YES continuity neutral and ground.

With 120v shore power:
- Breaker box - YES continuity between neutral and ground.
- Transfer switch, shore power input: YES continuity neutral to ground.

With 240v generator power:
- Breaker box - YES continuity between neutral and ground
- Transfer switch, generator input: YES continuity neutral and ground.

Note 1: I am testing the input side only of the breaker box.
Note 2: In the transfer switch, with no power being supplied, the generator input wires show continuity between neutral and ground, and also between all other wires - that is black to red, to white, to ground, and red to black, to white, to ground.
Note 3: My generator does take precedence over shore power, if that matters.

Re: Hughes Power Watchdog EMS indicating no neutral

Reply #8 –
Looks like everything tests out perfect.  I would say you have a bad HPW EMS.
 

Re: Hughes Power Watchdog EMS indicating no neutral

Reply #9 –
I have the power watch dog. Actually I have two of them. One is to plug in at the pedestal type and the other one I have permanently mounted inside under the bed. Since a previous owner took out the auto transfer switches and put in a manual one there was room for it. I also have a Hughes autoformer in there, and I put a plug in there for it but it's not plugged in unless I need it. I've had to replace the power watch dog at least once on each one. I'm sorry I don't remember exactly why now but there were issues with it not working properly. My memory is not as good these days so I can't remember exactly what went down with it, but I remember getting the same readings. I called the company and they replaced it. One thing about installing one of these, I found that trying to get those wires properly secured with the system that they use was no bueno. I found that putting ferals and then crimping them with a cat 5 crimper tool did the trick. I know I did a post on them somewhere here on the forums. The crimping tool changes as the federal from round to square and therefore holds the wire much better.