Wiring 3 smoke alarms and extractor fans

[diyer001]

Can I wire 3 smoke alarms and 2 extractor fans directly in to the 6amp fuse in the consumer unit? Do I need to put a 3amp external fuse box and if so can I install just one outside the consumer unit for all of them?

 

[breezer]

wire what you like to it. Question is is it ok to which the answer is NO, smoke detectors must be on their own circuit

 

[fubar]

detectors must be on their own circuit

Unless they also have battery power, in which case they may get their mains power from a shared MCB (perhaps by wiring from an adjacent lighting ceiling rose).

Even then I would highly recommend using a seperate MCB.

--
Michael

 

[John.Stitch]

if you have a fan in the bathroom then you need the 3A spur switch outside the bathroom.
The fan is wired into the light switch.

 

[diyer001]

Thank you for all your advise and comments. I'll wire the smoke detectors directly to the MCB and I'll take the power for the fans from the lighting circuit with 3amp spur.

If the rating for a device is 3amps and say you have three of them. Can you use one 3amp spur box to connect all of them or do you need a separate box for each?

 

[JPBOLDY]

Hi,

I just recently wired up an extractor van in my bathroom, which i bought from City Electrical Factors which has a draught vent inside which means any air coming in will be limited specially in winter when your in the shower!!!, anyway i did get advise from this site on how to get it wired up.

I didnt use a 3amp Spur as I connected the extractor fan from the wall and took the wiring into the loft, then connected the Switch Live, Permanent live and Netural into the light fitting, and the other wires into the extractor fan, then covered up the wires with Trunking to make it water tight then as a added protecttion i siliconed around the trunking at the sides and also all the way round the extractor fan as this one is not one that can fit tigithly into the wall and would look daft just seeing a little vent then some trunking.

Now the fan goes on when the light is on, then it stays on after the light is off as its connected by the P Live wire for the timer to kick in and is left for 5 minutes then will auto shut down you can get others without a timer or with a PIR sensor which come on when they dectect humidty levels put this could be annoying if it comes on at 3:00am in the morning and if your'e a light sleeper would wake you up, so thats why i optd for the timer one as i can adjust the timer settings according to the time of year i.e summer, autumn, winter.

I did at first connect up the fan wrong thats where this site helped me as i got the switched live and permanent live the wrong way round which cause the fan to go on with the light switch but then go off when it went off as i bypassed the timer as the timer runs on permanent live.

Hope this helps - as for some alarms i just use Argos ones battery powered when they on a low they beep and tell you to replace the battery more simple and easier to fit.....

If anyone has any ideas how i can wire up a extractor fan in my kitchen would be great - one problem is that i cant connect to the light fitting cause we have wooden floor down and has just been fitted, also the vent is above the window that i wanna use and without hacking into the wall to route to the light switch would be amajor task and cost as kitchen just been done as well, installing the fan wouldnt be a problem its just the wiring side

 

[breezer]

you could always put in an fcu adj the fan, lift the floorboards upstairs and tap into the ring.

you can have a fan with no timer and an integral pull cord

 

[ban-all-sheds]

I very much doubt if, after 3 weeks, diyer001 is still sitting there waiting for an answer, but if you are:

If the rating for a device is 3amps and say you have three of them. Can you use one 3amp spur box to connect all of them or do you need a separate box for each?

Can you multiply 3 x 3? Is the answer 3?

you can get others without a timer or with a PIR sensor which come on when they dectect humidty levels

PIR stands for Proximity Infra Red - it detects warm bodies, not humidity...

If anyone has any ideas how i can wire up a extractor fan in my kitchen would be great - one problem is that i cant connect to the light fitting cause we have wooden floor down and has just been fitted, also the vent is above the window that i wanna use and without hacking into the wall to route to the light switch would be amajor task and cost as kitchen just been done as well, installing the fan wouldnt be a problem its just the wiring side

It never ceases to amaze me how many people put down immovable floors, install new bathrooms and kitchens, finish off all the decoration, and only then think about the wiring....

 

[breezer]

you can get others without a timer or with a PIR sensor which come on when they dectect humidty levels

PIR stands for Proximity Infra Red - it detects warm bodies, not humidity...

sorry ban it doesn't, it stand s for passive infra red.

passive because it doesnt actually emit anything (contrary to popular belief)

a pir has two infra red diodes (back to back) that look at a segmented mirror ,or look through a fresnel lens.

in either case it has to "see" the scource of heat move from one segment (or area on a fresnel lens) to another, to show where these areas are the acompanying drawing has lines showing where it can see, these are (very often) confused as being beams, which they are not.

How ever there is such a thing as an Active infra red detector, that is in two parts, one is a light scource (usually infra red led) the other is an infra red receiver, now this DOES emit a beam of infra red light which has to be interupted to activate the reciever (depending upon configureation)

As the active infra red does use a beam and is at least 30 years old, people confuse the two.

you may wish to see this

 

[ban-all-sheds]

sorry ban it doesn't, it stand s for passive infra red.

Err - yes, it does, doesn't it, 99.99% of the time. Sorry 'bout that

 

[breezer]

you get your coat, and i have mine, see you in the pub

 

[ban-all-sheds]

Bl**dy long way to Peru - can we meet half-way, say in The Azores?

 

[diyer001]

In response to ban-all-sheds
Than you for you considered opinion and yes you are right I havn't been waiting all this time.

I must pick on the point you have made ie "Can you multiply 3 x 3? Is the answer 3". Can you please be kind enough to explain how this equation works when attempting to calculate current consumption of a electrical device, ie my lighting circuit is a 6amp and assuming that I have 3 lights connected, by your logic if I now connect 9 lights I 'll need 18amps?. Please do explain as I'm very keen to learn from a professional.

 

[breezer]

ban-all-sheds is still in the pub

 

[andemz]

ermmm.

Ban being a Professional?

If you are talking about the fact that he is an elctrician, does this mere title constitute to somebody being a professional?

This could be one interesting debate!

Is having a professional ethic essential to the existence of a professional, and in consideration to this how else might a professional be distinguished from members of other occupational groups?

So being an electrician, does this give one a higher social status, autonomy, self regulation, acting as a collective body and with a service orientation. Not to mention pay and conditions.

I think Beauchamp and Childress would have something to say about the term professioanl being used in the same sentence as the word "electrician".

In conclusion, in the truest definition from a philosophical position of the term professional an electrician ought not be considered as professional but highly skilled in a profession, namely that of "Electrics".