Power Meter Wiring in MCC Panel

[Histor]

Hi,

Is this wiring to Power meter is acceptable as per IEC?

We have metering CT installed on upstream of MCCB and connected to power meter.

Generally we install CT on Downstream of MCCB. So I got confused if it is acceptable as per IEC.

 

[che12345]

Histor (Electrical)(OP)24 Sep 24 08:56
'..Is this wiring to Power meter is acceptable as per IEC? We have metering CT installed on upstream of MCCB and connected to power meter. Generally we install CT on Downstream of MCCB. So I got confused if it is acceptable as per IEC'.
I have the following opinion for your consideration,
1. IEC recommendations are for "Safety" use of electricity. It does NOT interferes with the local practice, which are "safe".
2. Technically, both either CTs placed upstream or downstream of the CB are "safe" and measures/reads "correctly".
3. In some locations:
a) the utility's CT are located upstream of the CB in a compartment with sealed door; to prevent any accesses/tampering with by the consumer.
b) if the power (kW) or energy (kWh) meter and CTs are private/owner property, the CTs and voltage are usually taken downstream of the CB. Any rectification works can be done by switching off the CB.
Che Kuan Yau (Singapore)

 

[waross]

For what it is worth and for consideration:
The MCC is fed from;
"400 V supply from other Switchboard Panel".
Under the NEC, the breaker feedin g this panel should be lockable in the off position to allow safe work on the CT and meter.
Note: this does not apply to revenue meters which are the responsibility of the supply authority and are subject to different rules. including the sealed door mentioned by Mr. Che..

--------------------
Ohm's law
Not just a good idea;
It's the LAW!