Old building no grounds

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Radioshak9000

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New Mexico
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HVAC Technician
Hello,
This is my first post. Im an HVAC tech, i can only work from the panel going out. Today I was in an older building with no grounds. How is this possible? The 120v line on a reach in freezer meter set to continuity on my meter beeped to the metal case, also to neutral and the cases of the appliances appliances near the freezer. How is this freezer still running? I checked a gfi outlet in voltage with my meter and the gfi tripped when i put the other lead to a 3 compartment sink. Never saw that before. There is also 208 volt single phase with 1 leg being used for 120volt lights, a door heater, a drain heater for the walk-in cooler & freezer on 1 breaker. The 208 on its breaker (at least there are seperate breakers for both freezer & cooler) also powers the evaporator and its loads as well as the condensor and its loads on the rooftop and no ground upstairs. I do not claim to be an electrician but something is really wrong here. Can someone explain (more information i will add) this to me and point me in the right direction to educate myself as my co-workers have no answers. The dual voltage was not labeled either.
 
What is the wiring method for the branch circuits? Old buildings typically used a metal raceway as the EGC. Do you have any photos?
 
You might find this recent thread interesting:

Equipment Grounding Conductor History

Does anyone know when it became more common to pull an EGC, instead of using a metallic conduit as the main EGC? (For feeders and branch circuits) I have been doing research on this topic, but cannot seem to find when this practice changed.
forums.mikeholt.com
Your experience is not an unusual occurrence especially on an older building. 120v equipment will work fine without an equipment ground (think about 2 wire appliances) and using 1 pole of a 2 or 3 pole existing breaker for 120v loads in fairly common
 
208 3 phase is 208 V L-L. It is 115 V line to neutral. No reason you cannot use one line to neutral to feed 115 V loads and two lines for 208 V single phase loads.

As for continuity from a line to ground, you might be reading back thru the building transformer. It should be that way.

Nothing wrong with using metallic conduit as your equipment ground. In many ways it is a better grounding conductor than a wire.
 
petersonra said:
208 3 phase is 208 V L-L. It is 115 V line to neutral. No reason you cannot use one line to neutral to feed 115 V loads and two lines for 208 V single phase loads.

As for continuity from a line to ground, you might be reading back thru the building transformer. It should be that way.

Nothing wrong with using metallic conduit as your equipment ground. In many ways it is a better grounding conductor than a wire.
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Where are you getting 115V?
 
Little Bill said:
Where are you getting 115V?
Click to expand...
The
Little Bill said:
Where are you getting 115V?
Click to expand...
From the walk in freezer. One 120v leg from 208v Single phase condensor supply, do not know where the neutral is comming from probably the neutral in the panel. Although its a black wire neutral was ran a ways back just for the lights but it goes many other places for a 20 amp breaker. Lights in the walk in cooler then over to the freezer lights which we ususlly put another 20 amp breaker to be independant from each other. Then a door heater strip, drain heater refrigerant solnoid all this before the 208v supply goes to its intended place at the rooftop condensor, that has a compressor two fans, a crankcase heater, defrost control, defrost heaters and 2 fans down in the actual walk in evaporator. Took a while to trace back
 
Radioshak9000 said:
The

From the walk in freezer. One 120v leg from 208v Single phase condensor supply, do not know where the neutral is comming from probably the neutral in the panel. Although its a black wire neutral was ran a ways back just for the lights but it goes many other places for a 20 amp breaker. Lights in the walk in cooler then over to the freezer lights which we ususlly put another 20 amp breaker to be independant from each other. Then a door heater strip, drain heater refrigerant solnoid all this before the 208v supply goes to its intended place at the rooftop condensor, that has a compressor two fans, a crankcase heater, defrost control, defrost heaters and 2 fans down in the actual walk in evaporator. Took a while to trace back
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I was asking the poster that was saying one leg of a 208V to neutral was 115V, that is not a nominal voltage.
 
infinity said:
Good question 115 is mathematically impossible with 208 volts on a wye system. I'm sure he meant 120.
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Thank all of you for responding so quickly. Yes I did mean to say 120 volts, some appliances say 115volts at the plug on the appliance but not what is. 118.6v sometimes. 2minutes later its 118.3v. We all know what I mean. So the older buildings used the conduit as ground / neutral? But why did my gfi outlet "pop" when I went to the metal sink with one lead in the gfi & the other to the metal sink? ( its 118.2 now)
 
Radioshak9000 said:
Thank all of you for responding so quickly. Yes I did mean to say 120 volts, some appliances say 115volts at the plug on the appliance but not what is. 118.6v sometimes. 2minutes later its 118.3v. We all know what I mean. So the older buildings used the conduit as ground / neutral? But why did my gfi outlet "pop" when I went to the metal sink with one lead in the gfi & the other to the metal sink? ( its 118.2 now)
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Because the GFCI is looking for all current to be flowing in the hot and neutral conductors, any other path will trip the GFCI. The hot and neutral go through a CT in the device and if current does not add to zero (minus 6ma) it will trip.
 
Radioshak9000 said:
Thank all of you for responding so quickly. Yes I did mean to say 120 volts, some appliances say 115volts at the plug on the appliance but not what is. 118.6v sometimes. 2minutes later its 118.3v. We all know what I mean. So the older buildings used the conduit as ground / neutral? But why did my gfi outlet "pop" when I went to the metal sink with one lead in the gfi & the other to the metal sink? ( its 118.2 now)
Click to expand...

Metal conduit can serve as the EGC (what you’re calling ground), but it’s not allowed to serve as the neutral.
 
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