Bathroom extractor fans and 3 pole isolation: A source of much controversy

[sbelec]

The 3 phase isolator, especially if fitted outside the bathroom might not be sufficient under Electricity at work regs. The requirement is to work dead and on a circuit verified as dead and locked off in a manner which will not allow inadvert switching on.
At the side of the fan, no problem but outside with the potential of the door the electrician cannot be in control of the safe means of isolation. I have never seen a fan isolator with a locking facility.

 

[D Skelton]

Exactly! Which is what makes this 'local isolation for mechanical maintenance' a load of nonsense. An MCB however can be locked off.

 

[Andy78]

The 3 phase isolator, especially if fitted outside the bathroom might not be sufficient under Electricity at work regs. The requirement is to work dead and on a circuit verified as dead and locked off in a manner which will not allow inadvert switching on.
At the side of the fan, no problem but outside with the potential of the door the electrician cannot be in control of the safe means of isolation. I have never seen a fan isolator with a locking facility.

MK fan isolators are lockable I know that for sure.

 

[D Skelton]

Guys I'm not going to be disparaging towards sparks who fit isolators, what I will do however is point out to those who say that they are a 'requirement' in 100% of cases that they are wrong!

Edit: And let's be honest, there are far more pressing matters at hand than whether we need to fit fan isolators. I just thought it would be a useful post, I never thought it would turn into such a debate!

 

[Andy78]

I'm not disagreeing with you for the record. Was just chipping in with a bit of product advice. :smile5:

 

[Silly Sausage]

MK fan isolators are lockable I know that for sure.

True, got one at home.
Seem pretty crappy though, Two tiny plastic pins to lock the switch off.

 

[Andy78]

True, got one at home.
Seem pretty crappy though, Two tiny plastic pins to lock the switch off.

True, but if someone is going to make efforts to turn it on by breaking those pins, and ignoring the huge red flappy thing with a padlock dangling off it, then no amount of safeguarding and locking off is going to protect you from that person.

 

[Silly Sausage]

True! But remember, the world is full of idiots!

 

[Estimator]

On the legal standing of the BGB, I’m not a lawyer, but the Building Regulations are law, which everyone agrees on, and the approved documents give guidance on complying with them.

The following is an extract from Approved Document Part P 2013 Edition, Section 1 Design and Installation (Page 3)
“General
1.1 Electrical installations should be designed and installed in accordance with BS7671:2008 incorporating Amendment No.1:2011.”
So does mean that the BGB, is in a roundabout way, law?

Going back to the thread subject bathroom fans, fuses and isolators.

Change the pull switch controlling the lights to a DP pull switch (MK and Crabtree do them), connect the lighting feed and sw/wire to one pole.

From the lighting circuit take a Live and Neutral to a Fused Spur (fused to 3A).

Then run a twin from the spare pole of the pull switch to the spur.

Run a 3c to the fan.

Connect the lives from the 3c and the twin to the switch into the Load of the spur.

Joint the sw/wires from the twin and 3c in a Wago in the back of the Spur box.

If you really want to install a 3 pole isolator, run 2 twins and the 3c to it and make the connections there.

Both lives fused and isolated...

 

[D Skelton]

So does mean that the BGB, is in a roundabout way, law?

Technically no, but it sure as hell aint a guide!

 

[gonefishing]

Sorry, can't agree with any of that last paragraph or not...you are saying that no isolation is required close to the fan and then that no 3 pole device is required for isolation. Ever tried changing a fan on RCD protected circuit? you are really saying that you can remove all the connections, in most cases with permanent live and switched without causing the RCD to trip? TN system or not who takes the chance? Just because you interpret the regs your way doesn't make it correct does it?

I awlays fit a FCU fused to manufactures requirements and a 3 pole isolator and always 3+cpc cable and all accesible (usually above doorway).
I really can't believe some of the comments here concerning providing BS fuses protection to both permanent live and switched live, I would consider that wiring knowledge as 1st year stuff...

 

[D Skelton]

you are saying that no isolation is required close to the fan and then that no 3 pole device is required for isolation.

Just because you interpret the regs your way doesn't make it correct does it?

Find me some regulations then that prove me incorrect. If you can, I'll happy eat humble pie, until then why not keep your arrogant remarks to yourself.

And guess what, the beauty of non-statutory regulations is that they ARE often open to interpretation.

 

[i=p/u]

Yeah do what you do , but I install them beside it or above 2.2m

 

[sbelec]

I really can't believe some of the comments here concerning providing BS fuses protection to both permanent live and switched live, I would consider that wiring knowledge as 1st year stuff...

Not sure if I have misunderstood your quote, so appologies before i get shouted at, manrose fans installation wiring diagram show an FCU with a live split, 1 to light switch for switching and one direct to the fan as permanent live.
What puzzled me and this has now been answered within this thread was the small DP pull cord, one for fan switch live and one for light switch live. Haven't seen one for years and certainly my usual supplier said he had never seen one for years only the big shower switch.

If you follow the wiring logic above would that not do away with the need for the triple pole? Both feeds for the fan are through the fuse which can be removed and the fuse carrier locked open for safe isolation so regardless of location safe isolation is satisfied?

That will be my preferred route from now on, so now to shout at my supplier as I want DP 6 amp pull cord light switches.

Thank you Mr Skelton, for all we have had our disagreements the discussion you started has at least give me a standard which I am happy with and which has puzzled me for months if only it hadn't taken so long! The last fan wiring diagram would never have worked and all statute says that manufacturers instructions should be complied with - and that p!sses me off.
As a footnote, including myself, sometimes when writing briefly not all the meaning comes across. I know what I want to say but sometimes when I read back not even I understand it!

 

[Estimator]

To answer gonefishings' post #56 In my last post #54 I wasn't saying install or not install a 3 pole isolator, I mean't, it's up to your interpretation of the regulations whether to install one or not. All I was offering was a solution to the problem of fusing the Switch feed to the fan.

If you're changing the fan on a RCD protected circuit and it's wired through a Spur as my original post and the spur is switched off then then the neutral to the fan is isolated.

The DP Pull Switch is 16A, MK3151WHI or Crabtree 2163 or Legrand 061130

Discount-electrical.co.uk sell the MK