fused connection units
- Thread starter hark
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B
Big_Spark
hark said:
In theory Yes, however in practise NO.
The load a Fan and a shaver point will pull means that you can take these off the lighting circuit and there is then no loading problems.
You should never run shaver points or fans in bathroom from a ring main spur or a radial circuit for other purposes.
B
Big_Spark
il78 said:
I would think the Why is pretty obvious.
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Sorry, I still don't understand why not. Am an amateur at all this, but my Reader's Digest says do exactly this i.e. connect anything I need in the bathroom to an FCU outside the room.
Can someone please explain why this is the wrong thing to do?
Thanks.
Can someone please explain why this is the wrong thing to do?
Thanks.
Hey hark,
I agree !!
Perhaps no help to you ... but a similar vein.
I am ready to utilise a 2 pole FCU to supply my timed bathroom extractor fan, but because I need switched live from the lighting pull switch or ceiling rose as well as permanent live to fan, I can only envisage being able to fuse protect as per manufacturers instruction at 3 amp (lighting is 5 amp protected at source), when a single live is involved ie. before the switched live is created, after switching there are two 'lives' to fuse protect .... FCU protects only one.
So it it appears, on the surface, that 2 pole FCU could be used to supply the bathroom spur for simple lighting and fan, now all lives on that spur are protected at 3 amp, or are they?
Ready for the barrage now ....
P.
I agree !!
Perhaps no help to you ... but a similar vein.
I am ready to utilise a 2 pole FCU to supply my timed bathroom extractor fan, but because I need switched live from the lighting pull switch or ceiling rose as well as permanent live to fan, I can only envisage being able to fuse protect as per manufacturers instruction at 3 amp (lighting is 5 amp protected at source), when a single live is involved ie. before the switched live is created, after switching there are two 'lives' to fuse protect .... FCU protects only one.
So it it appears, on the surface, that 2 pole FCU could be used to supply the bathroom spur for simple lighting and fan, now all lives on that spur are protected at 3 amp, or are they?
Ready for the barrage now ....
P.
B
breezer
you can not do as you suggest because with a timed fan it needs a switched live to make it work, agreed?
the switched live comes from the lighting circuit, agreed?
so how are you going to isolate the fan supply with a fcu that at best can only isolate 2 poles, , if you use it to isolate the lives you are not isolating it as the neutral is still connected, so if yo isolate the neytral which live do you isolate, and if you dont you can back feed into the lights so they will work when off and vice versa.
extrator fans should be wired from lighting circuit, and have a 3 pole isolation switch
the switched live comes from the lighting circuit, agreed?
so how are you going to isolate the fan supply with a fcu that at best can only isolate 2 poles, , if you use it to isolate the lives you are not isolating it as the neutral is still connected, so if yo isolate the neytral which live do you isolate, and if you dont you can back feed into the lights so they will work when off and vice versa.
extrator fans should be wired from lighting circuit, and have a 3 pole isolation switch
Breezer - what pipme said was "2 pole FCU could be used to supply the bathroom spur for simple lighting and fan, now all lives on that spur are protected at 3 amp"breezer said:
So the permanent live for his fan comes straight off the supply from the FCU, and the switched live comes from the light, which is fed by the supply from the FCU. So switching off the FCU would isolate the fan completely. It would also isolate the light, which may not be ideal.
But yes, this is much better. Pipme - if you are concerned about how to fuse at 3A, why not have an unswitched FCU supplying the light in the bathroom, and then the normal wiring via 3-pole isolation switch to the fan?breezer said:
Did the fan not come with any wiring diagram? How and where do they suggest you fuse at 3A?
B
Big_Spark
Why should you not run supplies in a bathroom from a ring main even if it is via a fused spur?
Well there are several reasons for this, you may feel these are personal, but I like to think they are common sense.
1: Normally all lighting and bathroom fans are fed via the lighting circuit, this is irrelevent whether the fan is timed or not. To feed these via a circuit which you would not normally find running supplies in a bathroom is potentially dangerous. In the normal scheme of things it should be no more dangerous than any other electrical work, however if someone does not check a circuit is dead, because they have turned off the lights and assume it is dead (I know you should never assume but we are talking about the real world here) then there is a fair bet you will recieve a shock.
2: Each spur should only run one item, this means that your bathroom will require one spur for each item you wish to run off it (exception would obviously be multiple lights), therefore one spur for Light(s), one for fan etc. Each extra spur from a ring that is entered into the bathroom is a potential source for an electric shock as detailed above.
3: Upstairs ring mains are not necessarilly protected by RCD's or RCBO's, however non lighting circuit supplies in a fixed bath/shower room should be protected by an RCD/RCBO due to the increased dangers in these rooms.
4: If the upstairs circuit is protected by an RCD/RCBO, then nuisance tripping will likely occur due to moisture from steam etc in the bathroom, this may not always be a problem, but it is likely to be in a large number of situations.
5: If you call in an electrician to sort out your ring main due to the tripping, the cost will be higher for them to resolve any problems as they will likely not look in the bathroom for such circuit sections, they would only know if you tald them, and if you bought the house after the work was done you will not know too. By the time the problem is located, you could well have paid to have some or all of the upstairs ring rewired when it was not necessary to do so.
I think you will understand where I am coming from on this matter. I agree that in theory there is no reason to stop this, there is certainly nothing in the regs about it..HOWEVER, I spoke the technical dept of the IEE today, about something else, and asked about this, and they said that they would not recommend it for the very reasons I have highlighted above. The NICEIC also said something similar, but again fell short of condemning it or rather stating it shouldn't happen, just that they would "frown upon it"
Well there are several reasons for this, you may feel these are personal, but I like to think they are common sense.
1: Normally all lighting and bathroom fans are fed via the lighting circuit, this is irrelevent whether the fan is timed or not. To feed these via a circuit which you would not normally find running supplies in a bathroom is potentially dangerous. In the normal scheme of things it should be no more dangerous than any other electrical work, however if someone does not check a circuit is dead, because they have turned off the lights and assume it is dead (I know you should never assume but we are talking about the real world here) then there is a fair bet you will recieve a shock.
2: Each spur should only run one item, this means that your bathroom will require one spur for each item you wish to run off it (exception would obviously be multiple lights), therefore one spur for Light(s), one for fan etc. Each extra spur from a ring that is entered into the bathroom is a potential source for an electric shock as detailed above.
3: Upstairs ring mains are not necessarilly protected by RCD's or RCBO's, however non lighting circuit supplies in a fixed bath/shower room should be protected by an RCD/RCBO due to the increased dangers in these rooms.
4: If the upstairs circuit is protected by an RCD/RCBO, then nuisance tripping will likely occur due to moisture from steam etc in the bathroom, this may not always be a problem, but it is likely to be in a large number of situations.
5: If you call in an electrician to sort out your ring main due to the tripping, the cost will be higher for them to resolve any problems as they will likely not look in the bathroom for such circuit sections, they would only know if you tald them, and if you bought the house after the work was done you will not know too. By the time the problem is located, you could well have paid to have some or all of the upstairs ring rewired when it was not necessary to do so.
I think you will understand where I am coming from on this matter. I agree that in theory there is no reason to stop this, there is certainly nothing in the regs about it..HOWEVER, I spoke the technical dept of the IEE today, about something else, and asked about this, and they said that they would not recommend it for the very reasons I have highlighted above. The NICEIC also said something similar, but again fell short of condemning it or rather stating it shouldn't happen, just that they would "frown upon it"
1)
2) Apart from original question asked, no-one argued.
3) Depends on the design and locations. Do you wire the bathroom as a dedicated circuit?
4) All of the equipment should be suitably rated for use within the bathroom.
5) What....Me thinks any spark that see's a fuse spur on the wall may think its connected to the ringmain.....This then contradicts what you saying in another post about JB's under the floor, we dunno where you put them...
Remember you cant do things when it suits.......
You said it.....
2) Apart from original question asked, no-one argued.
3) Depends on the design and locations. Do you wire the bathroom as a dedicated circuit?
4) All of the equipment should be suitably rated for use within the bathroom.
5) What....Me thinks any spark that see's a fuse spur on the wall may think its connected to the ringmain.....This then contradicts what you saying in another post about JB's under the floor, we dunno where you put them...
Remember you cant do things when it suits.......
B
Big_Spark
Il, I thin k that cutting and pasting posts to suit your argument is ludicrous and as such at least I have justified my position, even if you disagree.
Lets have you justify yours instead of simply picking holes.
Lets have you justify yours instead of simply picking holes.
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According to some light fitting mfrs, any elec eqip. in z1 should be rcd protected, lighting included
Hi,
This really is interesting ... for the amateur anyway.
My timed fan and bathroom light are on a spur from the upstairs lighting circuit.
1968 house uses single core neutral cables. very neatly laid out !
Bathroom light and old fan were (electrician) wired as a spur ... I know where neutral and live are being tapped from. It is a real spur.
The fan is designed to run from 'Light switch or door switch', which really, to me, ties it into, in part, if not all, to the bathroom lighting, Fan requires 3amp fusing and isolation. The diagram supplied is schematic and simplified, does show the switched live leg tapping off the permanent live after the FCU and being created at the door / pullcord switch, see what I mean ..... light switch !!
Can you see where I am coming from ? Protect the whole spur with 2 pole FCU outside bathroom, provide supply to the pullcord switch, then after the switched live is created at the load side of switch, we have SW LIve, neutral, permanent live and earth all available for the light and fan, can isolate just prior to the fan with the 3 pole isolator.
As I see this, at the 2pole FCU Live and Neutral are switchable, with Live fused. This live is used to create the Switched Live and together with the neutral are all three switchable at the 3 pole fan isolator. This as a humble mech eng I see as fulfilling the Manuf requirements. But is it good enough?
Am itching to start the project ... But watching closely the tips and advice.
I think plenty others are too !!
Upon completion a sensible workmanlike diagram and small explanation would be worthwhile, placed into poly pocket and stored on clipboard in loft.
mmmm the digi camera will be of use here.
P.
This really is interesting ... for the amateur anyway.
My timed fan and bathroom light are on a spur from the upstairs lighting circuit.
1968 house uses single core neutral cables. very neatly laid out !
Bathroom light and old fan were (electrician) wired as a spur ... I know where neutral and live are being tapped from. It is a real spur.
The fan is designed to run from 'Light switch or door switch', which really, to me, ties it into, in part, if not all, to the bathroom lighting, Fan requires 3amp fusing and isolation. The diagram supplied is schematic and simplified, does show the switched live leg tapping off the permanent live after the FCU and being created at the door / pullcord switch, see what I mean ..... light switch !!
Can you see where I am coming from ? Protect the whole spur with 2 pole FCU outside bathroom, provide supply to the pullcord switch, then after the switched live is created at the load side of switch, we have SW LIve, neutral, permanent live and earth all available for the light and fan, can isolate just prior to the fan with the 3 pole isolator.
As I see this, at the 2pole FCU Live and Neutral are switchable, with Live fused. This live is used to create the Switched Live and together with the neutral are all three switchable at the 3 pole fan isolator. This as a humble mech eng I see as fulfilling the Manuf requirements. But is it good enough?
Am itching to start the project ... But watching closely the tips and advice.
I think plenty others are too !!
Upon completion a sensible workmanlike diagram and small explanation would be worthwhile, placed into poly pocket and stored on clipboard in loft.
mmmm the digi camera will be of use here.
P.
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