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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

  • 0
    Hi,


    The industry I work in currently have Air con units that have Two Rotary Isolators one inside & out on older Installations. Or a Rotary Isolator outside and a security key isolator inside on the newer units. 


    PC
  • 0
    I don't think BS 7671 is going to give you a simple answer to this - as far as the regs are concerned isolation can be as specific (e.g. single item of equipment) or as general (anything up to the whole installation) as you like - as long service conditions permit, and can be remote from the equipment provided it's capable of being secured (locked off). In either case it needs to be clear which devices isolates which equipment - so some decent labelling especially in the remote case.


       - Andy.
  • 0
    I came accross similar idea recently.

    Con unit with ring final, spured off to a SFCU just below that.

    In the cellar, directly below, A box of spaget with a prog mounted on it adjacent boiler, not an isolator in sight
  • 0
    Provided that the compressor unit feeds the evaporator unit (or the other way about) I don't see any problem at all. An EICR stops at the isolator.
  • 0
    Correct Chris, the aircon is an appliance, and its local wiring is not the fixed installation. A single isolator for the appliance is all that is necessary. Realistically only the aircon man is going to take the internal units apart, you wouldn't do it yourself would you?

  • 0

    davezawadi:

    Correct Chris, the aircon is an appliance, and its local wiring is not the fixed installation. A single isolator for the appliance is all that is necessary. Realistically only the aircon man is going to take the internal units apart, you wouldn't do it yourself would you?




    You wouldn't be allowed to!


    I have in the past tried to buy an air con system locally, but without the qualifications I couldn't. Mind you, there is always Fleabay. ?

  • 0
    Thanks for the responses everybody.
  • 0
    Three examples from domestic installations.
    • Where a hot water cylinder with an immersion heater is in an airing cupboard upstairs and its radial circuit is supplied from a dedicated MCB, although there may be a double pole control switch in the kitchen I still install a local double pole switch adjacent to the cylinder in the airing cupboard.

    • A PIR operated LED flood light mounted on an exterior wall can be wired directly into a lighting circuit supplied by a MCB without a local isolator or control switch.

    • Where there is a central heating boiler in a kitchen supplied from a SFCU in a airing cupboard that is elsewhere in the house I generally fit a three pole switch to isolate the boiler adjacent to it. But when the boiler is supplied by SFCU adjacent to it in the kitchen I don’t install any isolators for the central heating system equipment in the airing cupboard.


     Andy Betteridge
  • 0
    Whilst you may do that Andy, it is not part of BS7671. In fact I would doubt that many points of isolation make anything any safer, and possibly more inconvenient. Anyone working on any of this equipment has to be considered competent, and would therefore isolate and test for dead in the normal way. I have heard of an idiots charter, but taking the "its someone else's fault" route when a tool is required is a slippery slope to madness.
  • 0
    Okay, so how about the electric gates across the end of the driveway that are wired directly into a lighting circuit that supplies the lights on top of the gate pillars with the only point isolation being the single pole B6 MCB in the consumer unit?


     Andy Betteridge

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