Kevin Rose
01-02-2020, 04:00 PM
Hi
Just registered on this forum to ask this question.
I'm an electrician doing periodic inspection and testing, and the remedials resulting from them.
An issue has constantly come up as to whether an internal unit on A/Cs needs to have a local isolator to comply with the regs for switching off for mechanical maintenance.
There have been 2 schools of thought over this issue with others I am working with.
First one:
It is a an electromechanical piece of equipment and needs a local isolator even though it is being fed by an external unit that has it's own isolation.
Second one:
It is fed by the external unit and they are both one piece of equipment even though they are split with the two parts in different places. Turning off the isolator to the external unit isolates all the equipment.
In my opinion a local isolator is still needed as there is no way of knowing if the internal unit is definitely part the the external unit being isolated. It may just be off at the controls. If someone starts working on it it could become active if the wrong external isolator is locked off.
However, the term "local isolator" is not in the regs and they give no indication that an internal unit requires an isolator at that point as long as the system can be securely and reliably isolated on the main circuit feeding the unit.
I have come across many A/C units that have been installed by A/C engineers where they have not put an isolator on the internal unit. I was wondering if there is something that they know as to the fact that a local isolator on the internal unit is not required.
I was going to ask an A/C engineer about this but haven't seen one for ages.
Can anyone help me out on this issue?
Thanks
Just registered on this forum to ask this question.
I'm an electrician doing periodic inspection and testing, and the remedials resulting from them.
An issue has constantly come up as to whether an internal unit on A/Cs needs to have a local isolator to comply with the regs for switching off for mechanical maintenance.
There have been 2 schools of thought over this issue with others I am working with.
First one:
It is a an electromechanical piece of equipment and needs a local isolator even though it is being fed by an external unit that has it's own isolation.
Second one:
It is fed by the external unit and they are both one piece of equipment even though they are split with the two parts in different places. Turning off the isolator to the external unit isolates all the equipment.
In my opinion a local isolator is still needed as there is no way of knowing if the internal unit is definitely part the the external unit being isolated. It may just be off at the controls. If someone starts working on it it could become active if the wrong external isolator is locked off.
However, the term "local isolator" is not in the regs and they give no indication that an internal unit requires an isolator at that point as long as the system can be securely and reliably isolated on the main circuit feeding the unit.
I have come across many A/C units that have been installed by A/C engineers where they have not put an isolator on the internal unit. I was wondering if there is something that they know as to the fact that a local isolator on the internal unit is not required.
I was going to ask an A/C engineer about this but haven't seen one for ages.
Can anyone help me out on this issue?
Thanks