BrianHJR
DIY
Edited - please read right to the end!
Grateful for any advice regarding CT metering which seems to be generating inaccurate/implausible readings.
Our charity has a commercial building with 3-phase connection into a busbar chamber at one end - let’s call us ABC.
The rest of the chamber supplies three other switched fuses supplying another business nearby with 3 x single phase supplies - let’s call it XYZ.
The landlord had a contractor install 2 x Socomec Countis E42 units to meter our usage separately from the other business. They were set up so that XYZ meter records total usage, and ABC meter records only our usage.
Our ABC meter did not register any usage from day one, we let them know but they did nothing for months. Eventually they got the same contractors out to investigate and repair.
Since they did this our meter works, but the readings seem implausibly high, especially when compared to the XYZ usage.
Recently one of the directors observed that in 2.5 hours, our ABC meter incremented by 3KWH with just a few fluorescent light tubes on.
In the same time period, the business XYZ only had 1 KWH increment on their meter, despite being observed to have far more potential usage.
Does anyone have any experience of current transformers being inaccurate?
Could the issue be that we are using all 3 phases?
Might it just be a really bad or problematic install?
The landlord has tried to tell us it’s fine, but they did eventually say they’d get the contractors back out to have a look… we have considered installing our own check-meter but it’s a cost we really don’t need!
I’ve attached images of the install before the repair - I’ve no reason to believe they’ve changed the position of the CT clamps but I’ve not had a chance to look inside the bus bar chamber recently…
Our ABC connection is on the far right - the other 3 connections run to XYZ supplies…
Thanks in advance.
EDIT: Having thought about it a bit deeper, I’m pretty certain that they must have adjusted the positions of the CTs as the metering is now supposed to be completely separate… so the image will not be terribly useful in diagnosing the latest issues.
I’ll try to get an updated photo when I can… unfortunately it’s a two person job to remove the BBC cover since they mounted the meter box onto the front of it!
![[ElectriciansForums.net] Current transformer metering producing implausible readings](https://electricians.s3.eu-west-1.amazonaws.com/data/attachments/63/63289-b4c739c78ff215716a6889d2133e366e.jpg "[ElectriciansForums.net] Current transformer metering producing implausible readings")
Grateful for any advice regarding CT metering which seems to be generating inaccurate/implausible readings.
Our charity has a commercial building with 3-phase connection into a busbar chamber at one end - let’s call us ABC.
The rest of the chamber supplies three other switched fuses supplying another business nearby with 3 x single phase supplies - let’s call it XYZ.
The landlord had a contractor install 2 x Socomec Countis E42 units to meter our usage separately from the other business. They were set up so that XYZ meter records total usage, and ABC meter records only our usage.
Our ABC meter did not register any usage from day one, we let them know but they did nothing for months. Eventually they got the same contractors out to investigate and repair.
Since they did this our meter works, but the readings seem implausibly high, especially when compared to the XYZ usage.
Recently one of the directors observed that in 2.5 hours, our ABC meter incremented by 3KWH with just a few fluorescent light tubes on.
In the same time period, the business XYZ only had 1 KWH increment on their meter, despite being observed to have far more potential usage.
Does anyone have any experience of current transformers being inaccurate?
Could the issue be that we are using all 3 phases?
Might it just be a really bad or problematic install?
The landlord has tried to tell us it’s fine, but they did eventually say they’d get the contractors back out to have a look… we have considered installing our own check-meter but it’s a cost we really don’t need!
I’ve attached images of the install before the repair - I’ve no reason to believe they’ve changed the position of the CT clamps but I’ve not had a chance to look inside the bus bar chamber recently…
Our ABC connection is on the far right - the other 3 connections run to XYZ supplies…
Thanks in advance.
EDIT: Having thought about it a bit deeper, I’m pretty certain that they must have adjusted the positions of the CTs as the metering is now supposed to be completely separate… so the image will not be terribly useful in diagnosing the latest issues.
I’ll try to get an updated photo when I can… unfortunately it’s a two person job to remove the BBC cover since they mounted the meter box onto the front of it!
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