Re: Cooker hood wiring

Discussion in 'Misc DIY' started by Dave Plowman, Jul 28, 2003.

  1. Dave Plowman

    Dave Plowman Guest

    In article <3f250565$0$3135$>,
    John Greenwood <> wrote:
    > What are the options available to me to wire up a cooker hood, I can think
    > of three ways but whether these are allowed/legal I do not know:


    > 1. Wire it into the lighting circuit, but then there is no accessible
    > isolating switch.


    Neither is there for most lights. It presumably has its own on off switch?

    > 2. Wire it into an FCU hidden behind the hood, but then do I also need an
    > accessible isolating switch?


    Is it possible to wire it such that the cable comes out of the wall into
    it - ie behind it? If the cable comes out the top say near the back it's
    often the tidiest way to use an FCU or at least cord outlet even when
    wired off the lighting circuit.

    > 3. Wire it into the big red cooker switch.


    Not a good idea, IMHO.

    > I don't really want any visible wiring or socket/FCU. I favour number 2,
    > but I don't fancy adding a separate isolating switch as well.


    Can't see why you'd need one.

    > Anybody help with this?


    --
    *A bartender is just a pharmacist with a limited inventory.

    Dave Plowman London SW 12
    RIP Acorn
     
    Dave Plowman, Jul 28, 2003
    #1
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  2. In article <>,
    Dave Plowman <> writes:
    > In article <3f250565$0$3135$>,
    > John Greenwood <> wrote:
    >> What are the options available to me to wire up a cooker hood, I can think
    >> of three ways but whether these are allowed/legal I do not know:

    >
    >> 1. Wire it into the lighting circuit, but then there is no accessible
    >> isolating switch.

    >
    > Neither is there for most lights. It presumably has its own on off switch?


    ....but you need a means of isolating appliances containing
    motors.

    You could use an FCU or an unfused double pole switch,
    or a bathroom fan isolating switch (ignoring the 3rd
    pole, but it will have an appropriate legend on it).
    Some cooker hoods have quite high power fans nowadays,
    so check the loading on your lighting circuit first.

    >> 2. Wire it into an FCU hidden behind the hood, but then do I also need an
    >> accessible isolating switch?


    You need to be able to operate it for maintenance of the
    cooker hood, i.e. before you open or take the hood down.
    It doesn't need to be accessible for normal day-to-day use.
    If it's far enough away (or out of sight) of the cooker hood
    such that someone working on the hood could not be said to
    be in direct control of it, it needs to be a type of switch
    which can be locked off. Bathroom fan isolating switches
    are often of this type, although they don't come with the
    lock (it engages in two tiny holes either side of the
    rocker, which you probably haven't noticed unless you looked
    for them, holding it in the off position).

    BTW, and plug and socket is also acceptable means of
    isolation.

    >> 3. Wire it into the big red cooker switch.

    >
    > Not a good idea, IMHO.


    My cooker circuit has been turned into a switched radial
    circuit by fitting 3 socket outlets in place of the
    original hardwired cooker outlet. One has the oven plugged
    in, another has the gas hob ignition plugged in and the
    third was for some appliance previous occupant must have
    had in the cupboard under the oven. If your oven plugs
    into a 13A socket and you don't have electric hob, I see
    nothing wrong in doing this.

    --
    Andrew Gabriel
     
    Andrew Gabriel, Jul 28, 2003
    #2
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  3. In article <3f2539f3$0$18489$>,
    "Christian McArdle" <> writes:
    >>My cooker circuit has been turned into a switched radial
    >>circuit by fitting 3 socket outlets in place of the
    >>original hardwired cooker outlet.

    >
    > Provided the MCB/fuse is of a sensible rating, of course. (i.e. a 32A or 20A
    > B curve). This will usually be the case, although frequently cooker circuits


    It is in this case, and 6mm² cable.

    > are wired with higher ratings, such as 40A or 45A, which would need swapping
    > out. Also, you'll need to prove that the sockets aren't likely to be used
    > for outdoor portable equipment, as they would need an RCD/RCBO.


    Well, there aren't any RCD's in this house at the moment.
    If I get round to it before Part P comes into force, I will fit
    a nice new CU with separate RCD protection on each ring, and take
    the immersion heater off the ring circuit. If I don't get round
    to it in time, it will stay with no RCD protection and with the
    immersion heater on the ring circuit forever more, or until it
    causes a fire and burns the house down...

    --
    Andrew Gabriel
     
    Andrew Gabriel, Jul 28, 2003
    #3
  4. Hi Andrew,

    Thanks for your reply. I have decided to do the following:

    Install a 13A socket behind the cooker hood which will be completely hidden.
    The cooker hood will be plugged into this. The socket will be connected to a
    visible FCU at worktop level. The FCU being on the kitchen ring circuit.

    Does this sound as if it is in line with the regulations?

    Thanks,

    John

    "Andrew Gabriel" <> wrote in message
    news:bg38r3$5r6$...
    > In article <>,
    > Dave Plowman <> writes:
    > > In article <3f250565$0$3135$>,
    > > John Greenwood <> wrote:
    > >> What are the options available to me to wire up a cooker hood, I can

    think
    > >> of three ways but whether these are allowed/legal I do not know:

    > >
    > >> 1. Wire it into the lighting circuit, but then there is no accessible
    > >> isolating switch.

    > >
    > > Neither is there for most lights. It presumably has its own on off

    switch?
    >
    > ...but you need a means of isolating appliances containing
    > motors.
    >
    > You could use an FCU or an unfused double pole switch,
    > or a bathroom fan isolating switch (ignoring the 3rd
    > pole, but it will have an appropriate legend on it).
    > Some cooker hoods have quite high power fans nowadays,
    > so check the loading on your lighting circuit first.
    >
    > >> 2. Wire it into an FCU hidden behind the hood, but then do I also need

    an
    > >> accessible isolating switch?

    >
    > You need to be able to operate it for maintenance of the
    > cooker hood, i.e. before you open or take the hood down.
    > It doesn't need to be accessible for normal day-to-day use.
    > If it's far enough away (or out of sight) of the cooker hood
    > such that someone working on the hood could not be said to
    > be in direct control of it, it needs to be a type of switch
    > which can be locked off. Bathroom fan isolating switches
    > are often of this type, although they don't come with the
    > lock (it engages in two tiny holes either side of the
    > rocker, which you probably haven't noticed unless you looked
    > for them, holding it in the off position).
    >
    > BTW, and plug and socket is also acceptable means of
    > isolation.
    >
    > >> 3. Wire it into the big red cooker switch.

    > >
    > > Not a good idea, IMHO.

    >
    > My cooker circuit has been turned into a switched radial
    > circuit by fitting 3 socket outlets in place of the
    > original hardwired cooker outlet. One has the oven plugged
    > in, another has the gas hob ignition plugged in and the
    > third was for some appliance previous occupant must have
    > had in the cupboard under the oven. If your oven plugs
    > into a 13A socket and you don't have electric hob, I see
    > nothing wrong in doing this.
    >
    > --
    > Andrew Gabriel
     
    John Greenwood, Jul 28, 2003
    #4
  5. In article <3f25766f$0$11385$>,
    "John Greenwood" <> writes:
    > Hi Andrew,
    >
    > Thanks for your reply. I have decided to do the following:
    >
    > Install a 13A socket behind the cooker hood which will be completely hidden.
    > The cooker hood will be plugged into this. The socket will be connected to a
    > visible FCU at worktop level. The FCU being on the kitchen ring circuit.
    >
    > Does this sound as if it is in line with the regulations?


    Yes, but you don't need the FCU.
    If the plug can't be withdrawn without first dismantling or
    removing the extractor fan, then a double pole 20A switch
    will do (unfused as there is a fuse in the 13A plug).
    If you can get to the plug for such maintenance, then you
    don't even need the switch. You don't need to be able to get
    to the plug or switch easily for everyday use -- they are
    isolating switches for maintenance, and not required for
    functional switching (hood presumably has its own switches
    built-in for that).

    --
    Andrew Gabriel
     
    Andrew Gabriel, Jul 28, 2003
    #5
  6. Thanks Andrew, all a lot clearer now.

    "Andrew Gabriel" <> wrote in message
    news:bg3tvg$d1u$...
    > In article <3f25766f$0$11385$>,
    > "John Greenwood" <> writes:
    > > Hi Andrew,
    > >
    > > Thanks for your reply. I have decided to do the following:
    > >
    > > Install a 13A socket behind the cooker hood which will be completely

    hidden.
    > > The cooker hood will be plugged into this. The socket will be connected

    to a
    > > visible FCU at worktop level. The FCU being on the kitchen ring circuit.
    > >
    > > Does this sound as if it is in line with the regulations?

    >
    > Yes, but you don't need the FCU.
    > If the plug can't be withdrawn without first dismantling or
    > removing the extractor fan, then a double pole 20A switch
    > will do (unfused as there is a fuse in the 13A plug).
    > If you can get to the plug for such maintenance, then you
    > don't even need the switch. You don't need to be able to get
    > to the plug or switch easily for everyday use -- they are
    > isolating switches for maintenance, and not required for
    > functional switching (hood presumably has its own switches
    > built-in for that).
    >
    > --
    > Andrew Gabriel
     
    John Greenwood, Jul 28, 2003
    #6
  7. Dave Plowman

    Andrew McKay Guest

    On Mon, 28 Jul 2003 20:17:28 +0100, "John Greenwood"
    <> wrote:

    >Install a 13A socket behind the cooker hood which will be completely hidden.
    >The cooker hood will be plugged into this. The socket will be connected to a
    >visible FCU at worktop level. The FCU being on the kitchen ring circuit.


    I think I might be a little concerned about the environment that would
    exist behind the cooker hood. By virtue of the fact it is a cooker
    hood one expects the general area to get a bit warm, and maybe laced
    with condensation/steam and other environmentally unfriendly options.

    That probably doesn't make it a problem for the regs as such, but page
    2 of Electrical Commonsense #101 might apply.

    The other issue I would raise in this situation is that if you needed
    to take the power off that cooker hood fast, do you intend that the
    cooker hood has to be stripped before the mains to it can be
    disconnected? If so, that doesn't sound like an ideal situation. It'll
    be a right royal pain in the butt if the fuse to the cooker hood blows
    and you've got to take the whole thing apart to check it out!

    Andrew

    Do you need a handyman service? Check out our
    web site at http://www.handymac.co.uk
     
    Andrew McKay, Jul 28, 2003
    #7
  8. Dave Plowman

    BigWallop Guest

    "John Greenwood" <> wrote in message
    news:3f259562$0$18489$...
    > But hang on, can I place a 20A switch in the ring circuit just like a FCU?
    >

    <snipped>

    You won't need any FCU in the circuit if you're making the socket in as part
    of the ring main. If you're making the socket for the cooker hood a spur
    off from the ring main in the kitchen, then a fused spur unit can be placed
    beside the socket where you're taking the spur from. Then you take a single
    cable up to the socket behind the cooker hood.

    As long as the cooker hood can be completely isolated from the electric's,
    both live and neutral, for maintenance reasons, then that is all that is
    needed. This is why Andrew recommended either a double pole switch which
    breaks both live and neutral supply, or a switched fused spur if you were
    removing the plug.

    A switched fused spur with flex outlet would be the neatest way, as this
    means you're only taking one cable from the existing ring circuit, and
    connecting the flex in to the switched fused spur, which is quite within the
    regulations.
     
    BigWallop, Jul 28, 2003
    #8
  9. In article <3f259562$0$18489$>,
    "John Greenwood" <> writes:
    > But hang on, can I place a 20A switch in the ring circuit just like a FCU?


    Yes, switching the spur (and not breaking the ring;-)
    You have to have a fuse somewhere, be it in a FCU or in the
    appliance plugtop, but you don't need more than one, and
    it doesn't have to be at the beginning of the spur.

    --
    Andrew Gabriel
     
    Andrew Gabriel, Jul 29, 2003
    #9
  10. Dave Plowman

    Andrew McKay Guest

    On Tue, 29 Jul 2003 09:22:48 +0100, "John Greenwood"
    <> wrote:

    >Point taken Andrew, but how do I wire it so that no plugs/sockets/cables are
    >visible?


    Maybe a couple of ideas:

    1) Take the cable thru one of the cupboards at the side of the cooker
    hood, and have the socket in there (you do have a side cupboard to the
    cooker hood?).

    2) Channel down to beneath the work surface, and put the connection in
    a cupboard under there.

    3) Take the connection up and to the side, wired into a fused spur.

    Andrew

    Do you need a handyman service? Check out our
    web site at http://www.handymac.co.uk
     
    Andrew McKay, Jul 29, 2003
    #10
  11. Dave Plowman

    Fishter Guest

    Hi Andrew Gabriel
    In news:bg4cbk$hnd$ you wrote:

    >> But hang on, can I place a 20A switch in the ring circuit just like a FCU?


    > Yes, switching the spur (and not breaking the ring;-)
    > You have to have a fuse somewhere, be it in a FCU or in the
    > appliance plugtop, but you don't need more than one, and
    > it doesn't have to be at the beginning of the spur.


    Stupid question alert....

    What's an FCU? (Acronyms escape me sometimes....)

    --
    Fishter
    unhook to email me | http://www.fishter.org.uk/
    You're about one brain cell away from being a talking monkey
     
    Fishter, Jul 29, 2003
    #11
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