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Local Isolation For A/C Internal Units

Sparkymania
Hi

Doing EICRs, and the remedials resulting from them.


An issue had been raging as to whether an internal unit needs to have a local isolator.

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.


I have come across many A/C units that have been installed by A/C engineers and they have not put an isolator on the internal unit. I'm wondering if there is a reason that they don't or if it's just ignorance of the regs on their part. I would have thought their training would have included that. Is there something that they know that means they don't need to install an isolator to the internal unit?


Anyone have any thoughts?


Thanks

Parents
  • 0
    Although the regs is wooly I think the key is in the wording "Switching for Mechanical Maintenance". I would always include a local isolator adjacent the equipment. You wouldn't expect a mechanical servicing engineer to go searching for the external rotary isolator when all they've come to do is service an internal unit.


    I've just had 3 external units installed serving 9 internal units all with local isolation - for the sake of a tenner a unit I'd always install them.


    On another note a consultant just designed some internal AC units for me on a large public building all having local isolation but suggested wiring the AC units on local Lighting circuits which then became a totally different argument. They argued that they were low wattage units so its perfectly acceptable. I argued that if the circuit needs isolating safely for maintenance then you lose the lights in the floorspace areas which adds to the risk. Reply was you have emergency lighting for that. The argument rumbles on.
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  • 0
    Although the regs is wooly I think the key is in the wording "Switching for Mechanical Maintenance". I would always include a local isolator adjacent the equipment. You wouldn't expect a mechanical servicing engineer to go searching for the external rotary isolator when all they've come to do is service an internal unit.


    I've just had 3 external units installed serving 9 internal units all with local isolation - for the sake of a tenner a unit I'd always install them.


    On another note a consultant just designed some internal AC units for me on a large public building all having local isolation but suggested wiring the AC units on local Lighting circuits which then became a totally different argument. They argued that they were low wattage units so its perfectly acceptable. I argued that if the circuit needs isolating safely for maintenance then you lose the lights in the floorspace areas which adds to the risk. Reply was you have emergency lighting for that. The argument rumbles on.
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