Problem with Home 50 amp receptacle

[LittleBill]

In 2018 I had an electrician convert my electrical fuse service box to a 200 amp circuit breaker service and install a 50 amp service on side of my garage for my 5er. Other than an initial problem that required the electrician to come back and install a different receptable box, I haven't noticed any problems. I always connect a surge protector from habit when plugging my unit into it even though we have a whole house surge protector at the main box.

This past week my nephew from out of state parked his motorhome in my drive while staying with friends. He plugged in his surge protector first which indicated all was good. However when he plugged his cord in and turned his power on, his on-board EMS shut down and said he had an inadequate ground. He got around this issue by just plugging into a 120 outlet as he only wanted to keep his batteries topped off while parked.

So today I took my multi-meter and checked the wires at the box.

Here are the basic readings I got when the breakers where ON -
Hot1 to Hot2 - 244.3
Hot 1 to Neutral - 122
Hot 2 to Neutral - 122.1
Ground to Neutral - .43
Ground to Hot 1 - 103.3-105.3 (Initially got 89-90)
Ground to Hot 2 - 103.6-105.6 (Initially got 89-90)

Here are the basic readings I got when the breakers where OFF -
Hot1 to Hot2 - .058
Hot 1 to Neutral - 21.4
Hot 2 to Neutral - 21.38
Ground to Neutral - ..65
Ground to Hot 1 - 15.0
Ground to Hot 2 - 14.78

I'm assuming that the EMS was kicking out because of the low voltages when testing the Ground to the Hot legs. I also was kind of surprised at the values I got when the breakers were OFF. I noticed that the ground wire appeared to be connected to the box correctly.

I'm wondering if because it is quite a distance to the circuit breaker box to the receptacle box (even though all the wiring is in conduit & underground) that if I should connect to a grounding rod right at the box as this might correct the problem with the EMS? Suggestions.

Thanks and be safe -

 

[Mr. Dan]

Thread has been moved from the Off Topic forum to the Electrical, Charging Systems & Solar forum.

 

[Mike134]

See if you can find a cheap analog multimeter to check your readings when the circuits are off. You can get weird voltage readings with digital meters when the power is off

 

[LittleBill]

Thread has been moved from the Off Topic forum to the Electrical, Charging Systems & Solar forum.

Mr. Dan
Thanks, I looked at putting it there but thought it probably should go in off topic as it was not directly on an RV though associated with an RV. Hopefully next time I have something similar I will find the appropriate category.

Also thank you for your dedication as a member on the site team for the forum. Without individuals like you it wouldn't be a great forum like it is.

LittleBill
Be safe -

 

[Bama Rambler]

Looks like you have a high resistance ground. Possibly from a loose connection.
Ground to hot voltage should be pretty close to the neutral to hot value.

Turn off the breaker and check the tightness of all the Hot, Neutral, and ground connections in that circuit (at panel and receptacle).

You said that it's a good distance from breaker panel to the receptacle. How far is 'quite a distance'?
Also, do you know what size wire was used in the circuit?

 

[LittleBill]

Looks like you have a high resistance ground. Possibly from a loose connection.
Ground to hot voltage should be pretty close to the neutral to hot value.

Turn off the breaker and check the tightness of all the Hot, Neutral, and ground connections in that circuit (at panel and receptacle).

You said that it's a good distance from breaker panel to the receptacle. How far is 'quite a distance'?
Also, do you know what size wire was used in the circuit?

Good points to look at.
Will try to check the tightness of screws at both panel and receptacle sometime this week.
Don't have an idea for how far the distance really is. Off-hand I would guess at least 130 feet.
No I don't know what size wire but being I had a licensed electrician I assume he used the appropriate size based on load and distance. (I know that is making an *ss-u-me )

Thanks and be safe -

 

[JWood422]

Good points to look at.
Will try to check the tightness of screws at both panel and receptacle sometime this week.
Don't have an idea for how far the distance really is. Off-hand I would guess at least 130 feet.
No I don't know what size wire but being I had a licensed electrician I assume he used the appropriate size based on load and distance. (I know that is making an *ss-u-me )

Thanks and be safe -

Don’t assume any licensed electrician knows or cares. A highly-recommended electrician got the hot and neutral backwards and then told me it really didn’t matter. But then he came and corrected them anyway. Then he started bragging how he teaches wiring.

 

[Chuck_S]

What Jay just wrote!

For example I recently noticed the GFCI outlet in my garage didn't seem to be working so, being at least as smart and skilled as any licensed electrician -- I mean just how hard is it to change an outlet? -- I went to Lowes, bought a new one, and installed it. Still didn't work!

Took a real licensed electrician (one I've previously used and trust) to determine the entire circuit had been miswired 20 years ago during the home's construction. Nothing wrong with either the 20 year old or new GFCI outlet.

-- Chuck

 

[Bama Rambler]

...
Don't have an idea for how far the distance really is. Off-hand I would guess at least 130 feet.

130 feet isn't far at all. #6awg should handle that fine.

 

[jlankford]

Just curious... for your Ground to Neutral measurements, was the reading actually around 1/2 volt, or did the digital meter change scale and it was actually giving you a reading in mV?

 

[Larry-NC]

Thinking you are right!

Just curious... for your Ground to Neutral measurements, was the reading actually around 1/2 volt, or did the digital meter change scale and it was actually giving you a reading in mV?

I'm thinking you are right.

21 volts Hot to Neutral with the breaker open (both phases) is hard to fathom.

 

[Cdumesnil]

You have a poor connection between your neutral and ground. They should be tied together. There is usually a bonding screw the shorts a bar between the two busses. Make sure the connection is clean and tight. What you are experiencing is a floating ground. It is quite common. I've run into it several times.

 

[LittleBill]

Sorry for taking so long to respond.

Sorry fellow responders that I haven't responded on my issue in a timely manner.

Ok I will try to summarize what I have done so far with my low Hot 1 & 2 to ground voltage on my 50 amp service. As a reminder, the thing that started all this is my nephew's motorhome had an internal EMS that wouldn't allow him to plug into my 50 amp service as it detected low Hot to Ground voltage. He was able to utilize my 20 Amp service so his batteries could stay charged.

One suggestion was to get an analog meter, which I did. The readings for Hot 1 to Hot 2 (240V), Hot 1 to Neutral (120V) and Hot 2 to Neutral (120V). I also got a reading for the Hot 1 to Ground (103V) and Hot 2 to Ground (103V). All were similar to what I got with the digital meter

I then popped the cover to my receptable box and found the the Ground wire from the receptable was wired just to the box connection only and three wires for Hot 1 (black wire), Hot 2 (black wire tagged red) and Neutral (black wire tagged white) coming through the conduit to the receptable.

The conduit runs from the Main electrical box down 3 ft to outside wall, underground 100 ft from house to back of garage (with bends & turns), inside back of garage up 12 ft, across top rafter to front of garage 21 ft, down 3 ft to junction box (where wires for 20 Amp & 50 Amp split), across front of garage towards side wall 11 ft, down 5 ft, to side wall & box 1 ft. Let call it 160 ft as all measurements were close expect possibly the underground as I only stepped it off as best I could. There is access to the wires after the Main electrical box on the outside of the house just before it goes underground, on the back outside wall of the garage after it comes up from underground and at the junction box where the wires for 20 amp and 50 amp split.

There are 6 wires that were fed through the conduit to support both 20 Amp service to the garage household outlets and lights and the RV receptable 50 Amp service. After pulling the Junction box cover I found 3 wires Hot 1, Hot 2 and Neutral were the only wires going to the 50 amp service. There were three wires going to the 20 amp services - Hot (black), Neutral (white) and Ground (green). I also checked the 20 Amp service junction box where I found the Hot, Neutral and Ground connected to the 20 amp service properly.

I think I have been OK to plug my 5er and can continue to plug into the 50 amp service without any problems. However I think that I probably should perhaps do something to rectify the situation. But I think that trying to get an additional ground wire from the Main Electrical box through all the conduit to the 50 Amp box will be time consuming and not cost efficient.

I have given thought to a couple different ways that I might to be able to do.
1. Would be leave as is. By far easiest solution, as I still utilize a surge protector and don't think I should encounter any issues down the road as I only have it parked in my driveway for loading it when getting ready for a trip or unloading it after a trip.
2. Would be to tie the 50 amp receptable ground wire to the receptable Neutral wire. This would be similar to using a dongle plug in a generator so an EMS doesn't trip. Don't know that this would be to code or not.
3. Would be connect the 20 amp ground wire at the 20 amp service to the junction box so that the conduit would be grounded. Don't overly think this is what I want to do even though this may be the second easiest to do.
4. Would be to split the ground wire at the junction box at the front of the garage (that was run for the 20 amp service) and connect an additional ground wire to run to the 50 amp receptable using the single ground wire from from the Main Electrical box. This would be about 17 ft of wire to run through conduit. Again don't know that this would be to code or not either. Think this may be the best and safest solution that would not be too difficult to do IMHO.

Hopefully you will still throw me some recommendations or other suggestions my way.

Thanks & Be safe -

 

[Bob K4TAX]

The 50A service should be 4 wires. Hot #1. Hot #2. Neutral. Ground.

Yep, not wired correctly as I read. Licensed electricians. grrrrr! Have him come back and do it correctly! And on his nickle too.

Bob


There are 6 wires that were fed through the conduit to support both 20 Amp service to the garage household outlets and lights and the RV receptable 50 Amp service. After pulling the Junction box cover I found 3 wires Hot 1, Hot 2 and Neutral were the only wires going to the 50 amp service. There were three wires going to the 20 amp services - Hot (black), Neutral (white) and Ground (green). I also checked the 20 Amp service junction box where I found the Hot, Neutral and Ground connected to the 20 amp service properly.

 

[Larry-NC]

Some answers

If all the wiring from the point where the 20A and 50A split is in metal (EMT/thinwall conduit or rigid conduit (iron water pipe), then the wiring conforms to code. The ground connection to the outlet is made because the mounting bracket is common to (connected to) the green ground screw. This requires that the outlet be screwed down tightly.

In cities where EMT conduit is required (strong labor unions) this is common practice.

(NOTE: One thing I'm not sure about is whether current codes require that the ground wire be the same gauge as the power conductors on the 50 Amp circuit. It used to be the case (long time ago) that residential 20 amp circuits could have AWG 12 power conductors with an AWG 14 ground. Then (maybe 40 years ago) it changed and the all three 20 amp circuit conductors had to be AWG 12. I do not know if a 50 amp circuit has to have all four conductors as AWG 8 or whether the ground can be lighter. I'm assuming below that it can be lighter, i.e., AWG 12.

1. Would be leave as is. By far easiest solution, as I still utilize a surge protector and don't think I should encounter any issues down the road as I only have it parked in my driveway for loading it when getting ready for a trip or unloading it after a trip.

This is a bad idea. If a secondary fault occurs, e.g., a dangerous condition, e.g.,a "hot skin" condition will arise. Don't do this. A surge protector will not detect or prevent this condition.

2. Would be to tie the 50 amp receptable ground wire to the receptacle Neutral wire. This would be similar to using a dongle plug in a generator so an EMS doesn't trip. Don't know that this would be to code or not.

This is surely not conformant to current or old codes. Neutral and Ground should only be bonded together at the primary service panel.

3. Would be connect the 20 amp ground wire at the 20 amp service to the junction box so that the conduit would be grounded. Don't overly think this is what I want to do even though this may be the second easiest to do.

This is actually a good idea, as long as the connection between those points is all run in metal tubing (e.g., EMT(thinwall conduit) or rigid conduit). You don't need to make this connection because the mounting bracket on the 20 amp outlet is connected to the green screw terminal. You might be able to resolve this problem by simply tightening the mounting screws for the 20 amp outlet really tight.

4. Would be to split the ground wire at the junction box at the front of the garage (that was run for the 20 amp service) and connect an additional ground wire to run to the 50 amp receptacle using the single ground wire from from the Main Electrical box. This would be about 17 ft of wire to run through conduit. Again don't know that this would be to code or not either. Think this may be the best and safest solution that would not be too difficult to do IMHO.

Unless it's a straight run (no elbows or elbows you can open), this will be pretty tough to do, especially if you have to stuff an AWG 8 wire there to conform to current codes.

 

[LittleBill]

If all the wiring from the point where the 20A and 50A split is in metal (EMT/thinwall conduit or rigid conduit (iron water pipe), then the wiring conforms to code. The ground connection to the outlet is made because the mounting bracket is common to (connected to) the green ground screw. This requires that the outlet be screwed down tightly.

In cities where EMT conduit is required (strong labor unions) this is common practice.

(NOTE: One thing I'm not sure about is whether current codes require that the ground wire be the same gauge as the power conductors on the 50 Amp circuit. It used to be the case (long time ago) that residential 20 amp circuits could have AWG 12 power conductors with an AWG 14 ground. Then (maybe 40 years ago) it changed and the all three 20 amp circuit conductors had to be AWG 12. I do not know if a 50 amp circuit has to have all four conductors as AWG 8 or whether the ground can be lighter. I'm assuming below that it can be lighter, i.e., AWG 12.

This is a bad idea. If a secondary fault occurs, e.g., a dangerous condition, e.g.,a "hot skin" condition will arise. Don't do this. A surge protector will not detect or prevent this condition.

This is surely not conformant to current or old codes. Neutral and Ground should only be bonded together at the primary service panel.

This is actually a good idea, as long as the connection between those points is all run in metal tubing (e.g., EMT(thinwall conduit) or rigid conduit). You don't need to make this connection because the mounting bracket on the 20 amp outlet is connected to the green screw terminal. You might be able to resolve this problem by simply tightening the mounting screws for the 20 amp outlet really tight.

Unless it's a straight run (no elbows or elbows you can open), this will be pretty tough to do, especially if you have to stuff an AWG 8 wire there to conform to current codes.

One thing I failed to mention about the original wiring for the outlets and lights on the 20 Amp service is that the original wiring is not in conduit but it is Romex 3 wire (Black, White & Bare Wire). The conduit to these is only up to where a new junction box was installed so that the new wiring could be connected to the original wiring. My house and garage were built in 1972 and I'm assuming conduit wasn't specified in the electrical code.

I don't live in a city but in an unincorporated area of the county. I'm not sure what the code is. I do know that the new wiring to the garage was checked by the county inspector as there was an inspection tag left in the Main electrical box. I found it when I removed the cover to see what wires were passed through to the garage.

I probably will try to do the third option provided that the ground wiring is is the correct size. But being that there wasn't a separate ground wire run to the 50 amp receptable, it'll be my luck it's not large enough. If that is the case then I will try to get the electrician, who did the work, to come back and correct the situation. Because it has been over 6 1/2 years since the work was done to replace my old fuse box with a circuit box and install wiring to the garage, I'll probably be out of luck there too for them to come back and install a ground wire for free.

I probably won't be able to get anything done till spring now as I have a lot to do prior to leaving for Hunting Nov 19th and then Florida by Dec 10th. Wish me luck.

Thanks and be safe -

 

[LittleBill]

The 50A service should be 4 wires. Hot #1. Hot #2. Neutral. Ground.

Yep, not wired correctly as I read. Licensed electricians. grrrrr! Have him come back and do it correctly! And on his nickle too.

Bob

Only three wires were run to the 50 amp receptable from the Main Electrical box. It'll be tough to get the electrician after 6 1/2 years to come back and add a new ground wire on his nickel.

Thanks and be safe -

 

[Bob K4TAX]

"I do not know if a 50 amp circuit has to have all four conductors as AWG 8 or whether the ground can be lighter. I'm assuming below that it can be lighter, i.e., AWG 12."

With a 50A circuit, the ground wire can be one gauge smaller than the wires for L1 and L2. Neutral must be the same gauge as L1 and L2.

I strongly suspect,and could it be, the electrician used the conduit for the ground in place of pulling in another wire. Not sure if this is legal or not.
With wires in conduit, the current rating is different than wire in free air. Then there are different insulation requirements as well.

Bob

 

[TitanMike]

"I do not know if a 50 amp circuit has to have all four conductors as AWG 8 or whether the ground can be lighter. I'm assuming below that it can be lighter, i.e., AWG 12."

With a 50A circuit, the ground wire can be one gauge smaller than the wires for L1 and L2. Neutral must be the same gauge as L1 and L2.

I strongly suspect,and could it be, the electrician used the conduit for the ground in place of pulling in another wire. Not sure if this is legal or not.
With wires in conduit, the current rating is different than wire in free air. Then there are different insulation requirements as well.

Bob

NEC allows users of EMT or rigid conduit for ground as long as proper bonding fittings are used. At receptacle a grounding pigtail is often required to assure a low resistance ground so any ground fault detection device functions properly.

 

[Mike134]

You don't even need to use a pigtail if it's a metal box and metal conduit and the receptacle has a brass clip on one of the mounting screws to assure it is self-grounding.