**help** Should I Have An Isolator On My Extractor?

[Stevie wonder]

Hi guys,

I am in the middle of a dispute between my home builder as I don't have an isolator on my utility extractor fan (enviro-fan moisture activated unit).

Consequently it is running on silent tickover constantly and then automatically ramps up when required.

All other extractors in my property have isolators apart from this one. The property was built in 2011.

I am I the opinion that as moving parts are involved it should be isolated (like the 4 others in the house) However I am not an electrician and have very limited knowledge on this subject.

Any help and guidance would be gratefully appreciated.

Regards,

Steve.

 

[wozz]

So you have a trickle fan and a boost function. Is this what you have a problem with? You want to isolate it to stop it trickling?

 

[Stevie wonder]

Yes that is correct.

There is no means of stopping the unit other than turning the power off to the downstairs.

Steve

 

[Stevie wonder]

Is this not covered by BS 7671?

 

[Technician]

So you mean that to do maintenance/cleaning etc you have to

isolate all downstairs circuits?

 

[Technician]

One of the regs stated around page 35 to 40 concerns

the minimising of inconvenience in the event of a fault.

From what you say (subject to a bit more information

from you) it looks as if this bit of kit does not have its

own isolation device within the CCU/board.

 

[SPECIAL LOCATION]

The wiring regulations do not give specific guidance for every type of device you could possible connect onto any circuit....

It is more about ensuring circuits are design correctly for their overall loadings, cable types, shock protection etc....

BUT..

Wiring regulation 134.1.1 does specifically state that manufactures instructions should be followed when installing electrical equipment!

So if you can you get a copy of the fan manufactures installation instructions,    

{often their websites have manual you can download. if not ring their tech department}

Their wiring installation guidance may well say if any additional fusing and isolation is needed...

and then you can persue the installers for not following manufactures instructions!

As a general rule I would always fit some form of local isolator to every fan I install...

Its just good practice IMHO.

Welcome to the forum. Guinness

 

[Technician]

What is the make of this unit?

 

[ProDave]

Let's apply some common sense here.

The fan was designed to run at a constant trickle ventilation rate. So was this part of the building's overall ventilation design? if so then there may be a good reason for NOT turning it off.

But in any event, to enter into a dispute with the house builder over something this trivial seems a bit over the top.  If you really want an isolator, then it would be a lot quicker and a lot less grief just to employ a local electrician to come and fit one, and it shouldn't cost very much.

 

[Doc Hudson]

Knowing what a lot of builders are like nower days, quality -vs- speed -vs- cost etc, it could be just one of many snags that the homeowner is disputing?  Almost all fan blades get clogged with dirt, grease etc over time and most manufactures do recommend isolating the device to clean the blades. But it can be argued as to how this isolation is achieved and very few people actually do bother to ever clean any fan from the day it is installed to the day it is removed! 

Doc H.

 

[SLIPSHOD & SLAPDASH]

Hi. The quick answer is yes, you 'should' have an isolator, but its not the end of the world you haven't. Dave quite rightly pointed out the downfalls of having a on-off switch.

A large number of electricians dont know the reason for fan isolation switches. Its not  to isolate the electrics to make safe whist working as you could argue every single item in an installation needs them. Its due to the fan blades that could cause harm or back emf  as stated in reg (BS7671:2008)  537.3.1.1.

This is then followed up by 537.3.1.2 which states " Suitable  means shall be provided to prevent electrically powered equipment from becoming unintentionally reactivated during mechanical maintenance, unless the means of switching off is continuously under the control of any person performing such maintenance"  

So, if there is a pull cord on-off on the fan no further isolation is required. If on your fan there is a switch to turn off the humidity sensor (unlikely) then again, a further isolator is not required. 

There is a comment to BS EN 60204 within these regs, but that is not for the domestic extract fans but for large industrial machines. 

We always fit isolators, whether the regs require or not  as so many  people dont know and its only a couple of pounds and an extra 20 min to do the job.

So the bottom line in your case appears to be , Yes, there should be an isolator.

Edit, Then of course one could argue that just because a fan such as yours could start whilst carrying out maintenance, its not a risk as the fan blades are not accessible. Thats not reality correct in my view as even dislodged dirt could get thrown in to your eyes etc .

 

[steptoe]

No,

I fit loads of these, if its an Enviro-Vent, there is nothing in manu instructions to fit an isolator,

They come with a dual surface box with a fused spur (unswitched) and transformer fitted to it,

Specifically isolators are never fitted for the exact reason you want one,

so they cannot be turned off, they are designed for constant running.

 

[Apache]

Maybe Stevie Wonder just hasn't seen the isolator...........

[see what I did there?]

 

[Technician]

"Specifically isolators are never fitted for the exact reason you want one,
so they cannot be turned off, they are designed for constant running."
 

What does this do to the electricity bill, Steps?  Or is the power when on

trickle so low that it could be ignored?

 

[SLIPSHOD & SLAPDASH]

No,

I fit loads of these, if its an Enviro-Vent, there is nothing in manu instructions to fit an isolator,

They come with a dual surface box with a fused spur (unswitched) and transformer fitted to it,

Specifically isolators are never fitted for the exact reason you want one,

so they cannot be turned off, they are designed for constant running.

Some good points there. My opinion is that case the unswitched spur is the isolation, so reg 537.3.1.2 has been fulfilled.

I should have used the words 'Yes, a means of isolation should be fitted' & not an isolator  should have been fitted.

 

[steptoe]

"Specifically isolators are never fitted for the exact reason you want one,so they cannot be turned off, they are designed for constant running." What does this do to the electricity bill, Steps?  Or is the power when ontrickle so low that it could be ignored?

I have one in the van,

will take a look at the power consumption when I get home.

 

[ProDave]

Before making a decision I would take a good hard look at how the building is ventilated.

Building regs here demands an extractor fan in a utility room. I can honestly say, ours is there just to comply to get a completion certificate. It has never been turned on, and I can think of no reason why I would ever want to turn it on.

but if yours is a sealed house with mechanical ventilation, this fan may be a vital part of that.

 

[steptoe]

good point Dave,

 

[Technician]

This is how things changed within the double glazing industry.

The units were so tight that within some rooms there was an

accumulation of damp.  Following on from this there was then

a requirement to fit frames with "trickle" ventilation that could

not be closed off.

 

[ScottR]

No,

I fit loads of these, if its an Enviro-Vent, there is nothing in manu instructions to fit an isolator,

They come with a dual surface box with a fused spur (unswitched) and transformer fitted to it,

Specifically isolators are never fitted for the exact reason you want one,

so they cannot be turned off, they are designed for constant running.

I remember fitting these fans in the rewires we used to do,only thing we done was changed the unswitched fused spur to a switched one which was engraved.We use to get called out with the same problem the fan won't stop running.