Refrigerator on 2-wire receptacle

[jim mccloy]

I'm in the process of changing a service entrance for a customer who is currently not living in the dwelling. The house and wiring are very old and I noticed that his fridge is on a 2-wire circuit with no ground. What is commonly done in this situation? I know the code references for the replacing of receps of the nongrounded type...but I'm worried that something could happen with the right kind of conditions.

Rewiring the circuit to me would be the best route to go. What about replacing the 2-wire with a GFCI? I know we don't usually put fridges on GFCI'S but I'm worried about liability.

 

[bennie]

Re: Refrigerator on 2-wire receptacle

Jim: What are the right kinds of conditions that may cause problems?

 

[jim mccloy]

Re: Refrigerator on 2-wire receptacle

I guess I should have said under the wrong kind of conditions. I'm a new electrician and I'm just concerned that if something shorted to the frame or if a fault occured that someone could recieve a shock. NEC 250.114 states the types of equipment to be grounded. This circuit is not. I just felt it my responsibility to fix this situation.

 

[bennie]

Re: Refrigerator on 2-wire receptacle

Jim: Are there any conductive surfaces, that are grounded, within reach of the refrigerator?

[ May 20, 2003, 11:14 PM: Message edited by: bennie ]

 

[jim mccloy]

Re: Refrigerator on 2-wire receptacle

Yes, there is a gas range within a few feet...see here's why I'm concerned. I went into the kitchen to see if everything was working properly after I threw the main and I touched a voltage sensor inadvertantly to the fridge and it sounded off. So, and this will probably sound stupid, but I got my meter and put one probe to the neutral of the 2-wire and the other to the case of the fridge and read 64 volts.

 

[bennie]

Re: Refrigerator on 2-wire receptacle

Are you using a high impedance meter?

A static tester will sound off on an ungrounded appliance.

Measure the voltage from the refrigerator to the range surface, with a low impedance tester.

This setup has likely been functioning for a long time. There is many around the country just like this one.

I bought a rental house recently, everything was two wire ungrounded. Although I re-wired the entire house, it was more because of the age of the wiring rather than being two wire.

 

[jim mccloy]

Re: Refrigerator on 2-wire receptacle

When I go back out there today, I will test as you suggested. Another thing that isn't right (and this is probably common too) is that down at the panel, the branch circuit wiring that the refrigerator is on, is made up of newer #12-2 WHITH an equipment ground. But up at the receptacle it's just the two wire with no ground. So somewhere either behind a wall or in an inaccessible junction box an EGC from the panel is tied to the neutral of the 2-wire circuit for the fridge.

 

[jim mccloy]

Re: Refrigerator on 2-wire receptacle

I'm sorry: I should have said in my last post that I'm ASSUMING that the neutral wire of that 2-wire circuit is tied to the equipment grounding conductor of a newer section of #12-2 that runs to the service panel.

 

[gwz2]

Re: Refrigerator on 2-wire receptacle

I'll try to look-up the mention in an EC&M magazine of a father whose son was helping a friend move into a NEW home. They plugged the old two wire refrig into a garage receptacle. Later, to take a break he sat down on the floor an leaned against the refrig.
and was electricuted.

See 250.114 and 250.114(3) which has been in the NEC for many years !

 

[bennie]

Re: Refrigerator on 2-wire receptacle

That is correct. According to my books, 1968 was the first year this rule was in the code.

Unfortunately the largest housing boom in the nation was from 1946 to 1968.

Sitting on possibly damp concrete makes a good ground contact. An equipment ground wire may have prevented this tragedy. A ground contact could also burn clear. It is all problematic, not definite.

A non-conductive floor is definite, and would have prevented this tragedy with out question.

 

[jim mccloy]

Re: Refrigerator on 2-wire receptacle

Bennie: I use a fluke 337 true RMS meter. It's auto ranging. I'm unable to get back out there today to investigate any further but I've been thinking about it all day.

Basically what I have is a fairly new fridge (It's one of those stainless steel outer surface types) with a 3-prong plug which is attached to a cheater plug. It is then plugged into a 2-wire recep with no equipment ground and I have 2 voltage sensing instruments that have indicated the outer surface of this appliance has voltage on it.

I failed to mention in my post last nite (I was tired) that I plugged the fridge into one of my extention cords and then went to another receptacle that WAS grounded and still showed the case to be hot.

So now I'm suspecting that it's not so much the ungrounded 2-wire circuit that's the problem...which obviously it's a problem unto it's own, but there's something wrong with the refrigerator. I was told that this appliance is a "scratch and dent" model from sears and there are dents on the side and front. Is it possible that by being dented, the frame has come into contact with something that is energized i.e. a thermostat or some other contact and it's not enough to short it out but enough to make the case hot. Or, this referigerator also has an automatic ice maker in the top, and the water running through the system is what I'm reading and it's bleeding off to ground? Hope I'm making sense. I'm open to any replies from more experiencd electricians.

 

[bennie]

Re: Refrigerator on 2-wire receptacle

Jim: If you read voltage from the skin of the refrigerator to the neutral side of the receptacle, you have a problem. The reading should be 120 volts for a LG (Line to Ground)fault.

Your meter is a high impedance type.

A low impedance test is necessary. A lampholder with a 60 watt lamp is a good low impedance test.
Touch one lead to the refrigerator skin and the other to a known ground. If the light goes on, call the appliance service man.