Recessed electrical meters in the building, how are they connected.

Cartoon1

Member
Location
Florida
Occupation
Electrical Engineer
I have an old a two story old building. According to the owner it has a separate meter for each floor. The meters are recessed in the exterior of the building as shown in the pic 1 (no idea how they are connected and measuring electric consumption). There is a 400AMP main disconnect switch inside building behind the meters wall that has a single set of feeders go into the breaker and two sets come out of the breaker where each set goes into first floor interior panel (MLO) and second floor interior panel(MLO) (I presume, since i turned off the breaker and both first and second floor lost power). Is it correct to presume that since the meters and main disconnect are on the same wall just opposite sides of it, that the meters tapping the secondary side of breakers (the 2 sets) to measure electric consumption for each floor tenant before making their way to the floor interior panels in the building? Any help on this scenario would be appreciated, i have never come across this case before. Thank you.
 

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Todd0x1

Senior Member
Location
CA
If I had to guess its cold sequence metering with the main disconnect/breaker ahead of the meters. But you would expect OCP on the output of each meter and for the main disco to be sealed. Can you check permit records? I wonder if this is some sort temp fix that never got made right. Strange.
 

Cartoon1

Member
Location
Florida
Occupation
Electrical Engineer
If I had to guess its cold sequence metering with the main disconnect/breaker ahead of the meters. But you would expect OCP on the output of each meter and for the main disco to be sealed. Can you check permit records? I wonder if this is some sort temp fix that never got made right. Strange.
Weird setup agreed. No record drawings unfortunately. If it is a cold sequence meter, wouldn't turning off the breaker also turn off the meter?? Also, I agree that there was some change at some point but I don't see a code violation per say, unless I'm missing something.
 

growler

Senior Member
Location
Atlanta,GA
I have an old a two story old building. According to the owner it has a separate meter for each floor. The meters are recessed in the exterior of the building as shown in the pic 1 (no idea how they are connected and measuring electric consumption).
With an old 400 Amp 3 phase service I would assume they are useing CTs to measure current flow.
Someone would have to visit the site to see where they are located.
 

Hv&Lv

Senior Member
Location
-
Occupation
Engineer/Technician
Weird setup agreed. No record drawings unfortunately. If it is a cold sequence meter, wouldn't turning off the breaker also turn off the meter?? Also, I agree that there was some change at some point but I don't see a code violation per say, unless I'm missing something.
I would love to see a better picture of the meter to see the form.
It looks to be self contained metering, so no CTs would be required.
we have some like that. Customer puts the base up and then installs the wall finish.
I guess 1/4 air gap isn’t all that important…
 

Cartoon1

Member
Location
Florida
Occupation
Electrical Engineer
I would love to see a better picture of the meter to see the form.
It looks to be self contained metering, so no CTs would be required.
we have some like that. Customer puts the base up and then installs the wall finish.
I guess 1/4 air gap isn’t all that important…

I don't have one unfortunately, although i remember both were registering. So you are saying that one set cable on the secondary load side of main breaker going through each of the meters then it goes to its associated interior panel location? it would make sense, since the feeder cables rated for 400AMP and the load secondary size of the two set cables are each rated for 200A, so those meters could be rated for 200A possibly. thanks!
 

Cartoon1

Member
Location
Florida
Occupation
Electrical Engineer
I want to update this post. I went out there to the site and it turned out to be a cold sequence metering. You had a main feeder coming into main disconnect switch and then it split into two sets coming out to 2 (200A) rated meters. From the meters i found two seperate fused disconnects rated at 200A that went to each floor 200A interior panels. The small disconnects switches were hidden in a corner under the stairs that is why no one was able to find them.
 

Todd0x1

Senior Member
Location
CA
I want to update this post. I went out there to the site and it turned out to be a cold sequence metering. You had a main feeder coming into main disconnect switch and then it split into two sets coming out to 2 (200A) rated meters. From the meters i found two seperate fused disconnects rated at 200A that went to each floor 200A interior panels. The small disconnects switches were hidden in a corner under the stairs that is why no one was able to find them.

thanks for the update! Surprised the main disconnect didn't have a utility seal on it.
 

Cartoon1

Member
Location
Florida
Occupation
Electrical Engineer
thanks for the update! Surprised the main disconnect didn't have a utility seal on it.
The owner said that the original main had a water leak and it had to be replaced. I'm not sure if the utility were ever involved in it though.
 
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