IPX4 Fused Spur

Discussion in 'Electricians' Talk' started by Mr H, Jan 9, 2019.

  1. It has a main switch on it, therefore it is switch gear.
    spinlondon likes this.
  2. spinlondon

    spinlondon Screwfix Select

    Was about to post that the CU would not be able to have a Main Switch.
  3. Coloumb

    Coloumb Screwfix Select

    Fair points but I still maintain a fcu isn't allowed in zone 2.
  4. spinlondon

    spinlondon Screwfix Select

    If only you could back it up with something from BS7671.
  5. Coloumb

    Coloumb Screwfix Select

    What you mean like a definition?

    Something like...

    Switchgear. An assembly of main and auxiliary switching equipment for operation, regulation, protection (ie a fuse) or other control of an electrical installation.
  6. spinlondon

    spinlondon Screwfix Select

    Did you copy that from my post, or go look it up?
    Now if you want to lump FCUs and even SFCUs in with switchgear, fine.
    I expect you only install Amd 3 SFCUs and FCUs then?
  7. Coloumb

    Coloumb Screwfix Select

    I posted it first, fyi. So actually you copied me.

    I don't install Amd 3 SFCUs and FCUs, I install Consumer unit's, may also be known as a consumer control unit or electricity control unit, but not switchgear.

    Backed up as per BS7671.

  8. spinlondon

    spinlondon Screwfix Select

    Sorry, thought you were still disagreeing with me.
    Glad we got that sorted out.
  9. unphased

    unphased Screwfix Select

    Think I can settle this argument.

    Qu. Can you install an unswitched fused connection unit in zone 2 of a bathroom?

    Section 701 applies.
    Regulation 701.411.3.3 (i) Additional protection by RCDs applies. The circuit serving the location must be 30mA RCD protected (ie having the characteristics specified in 415.1.1).
    701.415.2 Supplementary protective equipotential bonding is not required if all of (iv), (v) and (vi) apply. If they don't then it is required.
    701.512.2 (ii) In zones 1 and 2 must be IPX4.
    701.512.3 In zone 2 an unfused connection unit is not switchgear, is not an accessory incorporating a switch and is not a socket.
    701.55 An FCU is not current using equipment, but this section would not apply to zone 2 anyway so irrelevant.

    A. So, in conclusion, yes, an IPX4 rated unswitched FCU on a 30mA RCD protected circuit and satisfied by the above Regs is allowed. A switched one would not be allowed.

    The lecturer who took the 18th edition course I sat recently taught me how to use the Regs properly and he has enlightened me. You cannot argue against the conclusion because the Regs are all there. :)
    Last edited: Jan 14, 2019
  10. unphased

    unphased Screwfix Select

    The definition of Switchgear precludes an unswitched FCU because the start of the definition is specific 'An assembly of main and auxilliary switching equipment'. An FCU is neither a main switch nor an auxilliary switch nor is it switching equipment; it is a protective device ie a fuse. If it contained a switch ie a switched FCU then it IS switchgear by definition.
  11. JP.

    JP. Screwfix Select

    I havent got a clue Spin
  12. Coloumb

    Coloumb Screwfix Select

    @unphased @spinlondon

    Imo a FCU is switchgear, it can be used to isolate a supply to equipment, you pull the fuse out, it switches off what it supplies. "Switch" gear. Section 5.1.2 in the OSG gives details and say's nothing about switch gear "having to have" a switch. But I must be mistaken.

    Imo the definitions in 7671 include both switch gear and consumer units. There are two separate definitions as a cu now has to be made out of non-combustible material, whilst switch gear does not. Seeing as switch gear and a CU's are separately defined it would appear to be OK to install a CU in zone 1 or zone 2 as a CU isn't specifically listed in any of the regs quoted and clearly it's not switch gear. Or do we now have to install switch fuses and isolators made from non-combustible materials? Or am I mistaken?

    Imo, the Table 8.1 in the OSG, Requirements for equipment (current-using and accessories) in a location containing a bath or shower

    the columns are headed..

    Zone Minimum degree of protection Current-using equipment Switchgear and accessories

    I must be mistaken in thinking that a FCU is not an accessorie. They must be two distinct and separate items.

    Same table for Zone 2 says...

    Only switches and sockets of SELV circuits allowed, the source being outside the zones

    Imo it appears to be ok to fit a FCU for, say, a towel rail but not for source of SELV ctts. Not sure how that works then? Weird. Still, must be mistaken.

    Seeing as the general idea about zones is that your not meant to have any kind of LV fixed wiring and/or supply within arms reach of the bath/shower I personally don't think it's a good idea to put it there, even if you would have to be pretty damn stupid to try to isolate or change the fuse on fixed equipment whilst in the bath, I would prefer to remove the option altogether in the first place. But I must be mistaken.

    But hey, what do I know? Probably I can't read 7671 properly as I'm not a chain wielding spark out doing it day after day like a boss. In fact, isn't it a shame that neither of you two posted straight up for the op, hey that's cool, pop in your fcu unit right there, just don't put a switch on it. Now he's had all the fuss and bother of putting it somewhere a bit more "sensible".

    Crack on.
  13. spinlondon

    spinlondon Screwfix Select

    Do you often jump into the bath with your terminal driver and spare fuses?
  14. Risteard

    Risteard Well-Known Member

    The usual (and incidentally the only correct) way of spelling that word is "accessory".

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