Discussion in 'Electricians' Talk' started by mrppp, Oct 12, 2017.

  1. Coloumb

    Coloumb Well-Known Member

    It's not that mate, what ristard means is you could say, have a 20a breaker on on 1.5mm flex as the load is unlikely to be exceeded. I wouldn't do it like that basically as I'm a bit anal.
    mrppp likes this.
  2. mrppp

    mrppp Member

    So is it basically down to preference if one can't be bothered to isolate at consumer unit stick an local isolation in, or unless manufacturer says you need one?
    Last edited: Oct 12, 2017
  3. JP.

    JP. Screwfix Select

    Fair enough cant find table 53.4 in yellow osg, however the notes do say that the use of circuit breakers can be used for functional switching, however the manufacturer should be consulted to establish suitability.

    5.1.1 section (b) Isolation and Switching

    As I thought in TT situations a dp switching mode should be used, which I presume/logically means dp mcb at intake position (db) and of course if you also fit a local isolator this will be dp also.

    So basically, and in a nutshell, it all boils down to what the manufacturers stipulate - cant argue with that.
    Last edited: Oct 12, 2017
  4. Comlec

    Comlec Active Member

    Mrppp you asked a very precise and reasonable question to start this post.
    I gave the simple answer - NO. And the source to the regs was quoted to support this.

    However as Bazza said there are other design requirements to take on board.

    Is not a question of "being bothered" it is down to good circuit design. I am sure you will install a circuit that complies with the regs, takes into account the manufactures requirements, the expected use by the customer and the current fashion in the placement of electrical fittings. This is what makes you the electrician. After all it is your name on the cert.
  5. Bob Rathbone

    Bob Rathbone Active Member

    Cookers, water heaters and the like must have a local double pole isolator, ie a cooker control unit within 2 m of the appliance. This is for mechanical and electrical isolation and for emergency isolation. Surely, this provision has not been removed from the 17th when I wasn't looking?
  6. JP.

    JP. Screwfix Select

    Its pages 49/50/51 in the yellow osg Mr C.
  7. Comlec

    Comlec Active Member

    I can find the Water heaters reg
    554.3.3 The heater or boiler shall be permanently connected to the electricity supply through a double-pole linked switch which is either separate from and within easy reach of the heater or boiler or is incorporated therein, and the wiring from the heater or boiler shall be connected directly to that switch without the use of a plug and socket-outlet; in addition, where the heater or boiler is installed in a room containing a fixed bath, the switch shall comply with Section 701.

    But can't find any reference to DP isolation for cookers. Maybe not looking hard enough:)
  8. Bazza

    Bazza Well-Known Member

    The G=guide. Not a regulation.

    It is also mentioned in the "Electricians Guide to the Building regulations"

    Local isolation for and oven/ cooker/ hamster wheel is not in any Building regulation either.
  9. JP.

    JP. Screwfix Select

    Myself I will always use local isolation for cookers/hobs Bazz, but now appreciate the fact that in some cases if you want to omit it you can..obviously this will be subject to manufacturers stipulations on the matter.

    I could not imagine a scene where if no local isolation could be used I would then go ahead without the isolation, it just will not happen.

    Being serious Bazz, just say for one minute you fitted the cooker circuit with no local isolator because the manufacturer or Building Regs etc showed that it was not necessary..fair nuff isolator is in the db for the circuit.

    Now one day the cooker breaks down and is uneconomical to repair, so a new unit is purchased. In the cooker handbook the manufacturer states that local isolation is required.

    Now what do you do? go ahead and fit it with no local isolation and break the regs?

    Cant say owt else Bazz. So as a diyer I would always fit a local isolator, whether it was needed or not at that period in time, in other words I have given the cooker circuit more latitude.

    Not being argumentative Bazz...just my tuppence worth m8.
    Davidc657 likes this.
  10. Bazza

    Bazza Well-Known Member

    No such thing in the regs for cookers. Its a myth. Immersed water heaters, yes that's in the regs 554, something IIRC.

    How long since you looked in the regs? For cookers, It isn't there in the 17th, I don't think it was there in the 16th.
    Its one of those things that people believe has to happen, and it doesnt. Its folk lore, architects put it in.
  11. Comlec

    Comlec Active Member

    Now I received my Yellow OSG I’ll look it up.

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