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Local Isolation For A/C Internal Units

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

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  • Ajjewsbury

    You misunderstood what I meant.

    That is exactly the way I would do it to make sure I was operating the correct device for isolation.

    What I was saying was that if a series of machines were already isolated and locked off at remote isolators then the one you was working on would already be dead. In that case you couldn't test live first, isolate then test dead to confirm. Re-read what I wrote. Having an isolator local to the machine you would be confident that you have isolated the machine being worked on.


    Regarding the second bit you commented on. Yeah! If you want to be hung, draw and quartered. Were talking labs, workshops etc. You can't go turning off other equipment just to work on one.
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  • Ajjewsbury

    You misunderstood what I meant.

    That is exactly the way I would do it to make sure I was operating the correct device for isolation.

    What I was saying was that if a series of machines were already isolated and locked off at remote isolators then the one you was working on would already be dead. In that case you couldn't test live first, isolate then test dead to confirm. Re-read what I wrote. Having an isolator local to the machine you would be confident that you have isolated the machine being worked on.


    Regarding the second bit you commented on. Yeah! If you want to be hung, draw and quartered. Were talking labs, workshops etc. You can't go turning off other equipment just to work on one.
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