Testing ACBs during Periodic inspection

[arashabb]

Hello everyone!
Has anyone been asked to test the main building incomers like ACBs as part of Periodic Inspection? If yes, do you give this part of the work to 3rd party? and what is the process and how you verify the report?
some of my bigger clients are asking for this test to be done.
Thanks in advance

 

[James]

I am pretty sure that ACB's should be serviced at intervals recommended by the manufacturer.
surely testing of them would be part of the service?

 

[arashabb]

I am pretty sure that ACB's should be serviced at intervals recommended by the manufacturer.
surely testing of them would be part of the service?

I am not sure.I believe they prefer to deal with just one company for testing the whole installation

 

[Nigel]

it would be best to clarify what the client means by testing.

ACBs should be racked out and various internal checks done periodically. Also at least once a year ACBs should be switched to exercise the springs. If there is a PLC this should also be confirmed as operational and all batteries and chargers conformed as in good order.

I would not entertain using any one other than a competent person to rack out an ACB and carry out the internal testing.

The switching and testing the PLC is something we do internally annually but we do have a level of competence to do this and a sound knowledge of the system it is not the competence required to rack out and test internally an ACB.

 

[arashabb]

it would be best to clarify what the client means by testing.

ACBs should be racked out and various internal checks done periodically. Also at least once a year ACBs should be switched to exercise the springs. If there is a PLC this should also be confirmed as operational and all batteries and chargers conformed as in good order.

I would not entertain using any one other than a competent person to rack out an ACB and carry out the internal testing.

The switching and testing the PLC is something we do internally annually but we do have a level of competence to do this and a sound knowledge of the system it is not the competence required to rack out and test internally an ACB.

I guess they want to make sure the springs would work properly and disconnects the load if they want to manually switch it off . also in case of a fault, it trips safely. which if I am not wrong, means all the procedure that you have mentioned shall be done and it is better to be done by a specialized company not part of general fixed wiring tests

 

[snowhead]

The ones I've seen tested were;

Mainly 2000amp, but size won't have too much effect on the costs.
Tested by a specialist
Required isolation of the (11kv) incomer by the DNO
Consisted of inspection / torque check of terminations.
Verification of settings to suit site
General condition check
Simulated load test using a test rig and a built in test facility.

Replacement with spare if faulty or failed test.

This was a new program set up after a series of ACB failures.
The failure wasn't to trip it was failure to reset due to springs / levers jamming in the open position.

As per ESSEX, they should be operated routinely.

 

[David Prosser]

The ones I've seen tested were;

Mainly 2000amp, but size won't have too much effect on the costs.
Tested by a specialist
Required isolation of the (11kv) incomer by the DNO
Consisted of inspection / torque check of terminations.
Verification of settings to suit site
General condition check
Simulated load test using a test rig and a built in test facility.

Replacement with spare if faulty or failed test.

This was a new program set up after a series of ACB failures.
The failure wasn't to trip it was failure to reset due to springs / levers jamming in the open position.

As per ESSEX, they should be operated routinely.

Hi Snowhead Why did the HV need isolating to test the ACB ?

 

[Bobster]

Hi Snowhead Why did the HV need isolating to test the ACB ?

Not all ACB's are able to be racked out for servicing.

Also, if it suspect that there maybe something wrong with it. Safer to have 0 load or potential there.

Although normal practice to de energize the LV side first then the HV.

 

[James]

Hi Snowhead Why did the HV need isolating to test the ACB ?

Often the acb is directly connected to the transformer.
In that case,
That is the only way to isolate it.

 

[snowhead]

Hi Snowhead Why did the HV need isolating to test the ACB ?

As others;

Most were mounted within the Transformer terminal cabinet.
Incoming connections to the ACBs were checked as well as outgoing.

 

[Megawatt]

I guess they want to make sure the springs would work properly and disconnects the load if they want to manually switch it off . also in case of a fault, it trips safely. which if I am not wrong, means all the procedure that you have mentioned shall be done and it is better to be done by a specialized company not part of general fixed wiring tests

They also probably put a full load on it to make sure it trips

 

[netblindpaul]

They also probably put a full load on it to make sure it trips

They use secondary injection into the protection unit to test the trip of the main breaker.

 

[Megawatt]

They use secondary injection into the protection unit to test the trip of the main breaker.

Paul I’ve been on many shutdowns where we rack out all breakers and give them to another company whose already set up on site testing them. Long days