switch for 2 speed inline extractor fan

VACN · 11-07-2023 8:06pm #1

Hi! Where I can get such switch?

kirk. · 11-07-2023 9:59pm

What is it a 4" inline

Do you need 2 speeds

VACN · 12-07-2023 4:22am

https://www.boards.ie/discussion/comment/120839525#Comment_120839525

6" multifan with timer.

2 speed is an option, so why not have it.

kirk. · 12-07-2023 9:46am

That's an xpelair timer model. May not be same as yours. 21 is high/low wiring

On-off is ST , a one-way switch

High-low is S , a one -way switch

How you control it is up to you. Needs an isolator in the vicinity of fan and fusing according to manual

You'd need to check the wiring diagram for your fan.

kirk. · 12-07-2023 10:14am

I have an inline fan which extracts steam

I'd only be using max anyway

You could have something like low comes on with bathroom light for odours and then humidistat switches fan to high for steam

Up to you really

VACN · 12-07-2023 2:35pm

>>> xpelair timer model

Yes same type, same diagram.

>>>I'd only be using max anyway

If my search fails, I will resort to this option.

kirk. · 12-07-2023 6:22pm

No mention of fusing , fan has thermal overload protection

Fusing would complicate the wiring because it has to be wired before everything else

Fan above needs 4-pole fan isolation if using max/min , probably one of the rotary isolators fitted near fan

VACN · 12-07-2023 7:21pm

>>>Fan above needs 4-pole fan isolation if using max/min

I'm not an electrician, so this information just wooshing over me.

From your post, I can infer the importance of simplifying connections for the sake of reliability.

If so, then I'm all for it.

Reliability first.

hesker · 12-07-2023 7:56pm

https://www.boards.ie/discussion/comment/120843167#Comment_120843167

Why could you not use a 2P isolator on the L N feed before QF

kirk. · 12-07-2023 8:10pm

https://www.boards.ie/discussion/comment/120843559#Comment_120843559

You're breaking the supply into the fan so you can safely work on fan

The only safe way to do this is to break all live conductors in the vicinity of the fan ie: 4-pole

Basically disconnecting the 5-core flex right before the fan

Anything else is a lottery in terms of what's off

10-10-20 · 14-07-2023 7:13am

https://www.boards.ie/discussion/comment/120843433#Comment_120843433

Safety first, reliability next if you want.

kirk. · 14-07-2023 8:42am

https://www.boards.ie/discussion/comment/120849097#Comment_120849097

How would you control that ? Is it worth bothering with 2 speeds?

10-10-20 · 14-07-2023 10:35pm

https://www.boards.ie/discussion/comment/120849365#Comment_120849365

Dual relay such as a dpdt. Two speeds are handy alright as you stated for humidistat switches and the like.

kirk. · 14-07-2023 10:59pm

https://www.boards.ie/discussion/comment/120853123#Comment_120853123

Dual relay?

10-10-20 · 15-07-2023 9:22pm

https://www.boards.ie/discussion/comment/120853176#Comment_120853176

Yes dual pole, DP.

16-07-2023 7:14am

https://www.boards.ie/discussion/comment/120843559#Comment_120843559

Correct answer, this would be best.

kirk. · 16-07-2023 3:14pm

https://www.boards.ie/discussion/comment/120857256#Comment_120857256

You're wrong but explain how you isolate with 2-pole with a 5-wire supply to fan

Regulations say you switch all live conductors

kirk. · 16-07-2023 3:31pm

https://www.boards.ie/discussion/comment/120856726#Comment_120856726

What for , you can switch direct?

Switch feed from bathroom light and switch feed from humidistat or whatever way you want

16-07-2023 7:23pm

https://www.boards.ie/discussion/comment/120858636#Comment_120858636

Simple, the 2 pole isolator switches off the phase and the neutral upstream of the point that the circuit becomes 5 wires.

In other words wire from the supply to 2 pole isolator, from there wire to the 2 speed switch and from there wire to the fan.

That way when the 2 pole isolator is in the open state all conductors are disconnected.

This complies fully with the regaultions.

kirk. · 16-07-2023 7:26pm

https://www.boards.ie/discussion/comment/120860062#Comment_120860062

No it doesn't

The wiring may be altered later downstream

There is no reason to use 2 pole when 4 pole is the only safe option

3-pole is standard for domestic fan with overrun as per rules

2 speed with overrun will be 4 pole switching all lives

16-07-2023 7:36pm

https://www.boards.ie/discussion/comment/120860082#Comment_120860082

1) If the wiring is altered downstream it makes no odds in terms of safety as the circuit has been completley isolated upstream.

2) I don't agree that 4 ploes is the "only safe option". Please demonstrate how this is the case.

3) The rules do note state that a 3 pole isolator is mandatory for a domestic fan with overrun. If you disagree show me the rule. There are often differnet ways to achieve the same goal in a way that complies with the rules.

4) What is mandatory is the isolator switches all live conductors (which includes the neutral), I have demonstrated how this can be achieved with a 2 pole isolator.

kirk. · 16-07-2023 8:08pm

1)For example someone wires fan from a socket spur Later someone decides to control low speed using a switched feed from bathroom light bypassing' isolation'

Why would you even isolate upstream when you can isolate supply into fan downstream where isolator is located

Makes no sense

kirk. · 16-07-2023 8:19pm

Any fan control using the bathroom light the isolator has to go downstream of bathroom light switch(rules)

Hence requires multipole (rules)

If it was independent of bathroom light you could argue you can fit a DP upstream

Same risk arises wiring may be altered later to include bathroom switch wiring

kirk. · 16-07-2023 8:46pm

https://www.boards.ie/discussion/comment/120860062#Comment_120860062

I would say now you're right it's possible to use 2-pole isolation upstream of controls according to rules

1)Wiring would need to be separate to bathroom light

1)I would consider it bad practice and don't know why it would be done this way

It's definitely not the 'best' method

Simply break the supply into the fan

16-07-2023 9:36pm

https://www.boards.ie/discussion/comment/120860433#Comment_120860433

Ok, so it would seem that we agree that it is permissible.

I would consider it best practice to use the 2 pole as I described, you have a different view. Let’s agree to disagree.

The rules can’t prevent people from altering compliant wiring, in fact nothing can. I think we can also agree on this.

kirk. · 17-07-2023 10:13am

Agree I misinterpreted breaking all lives

Disagree on best practice 'if' possible to use DP isolation

kirk. · 17-07-2023 2:25pm

2011

What is your reason for stating that isolating upstream is best practice. I notice you didn't backup that statement with any evidence whereas i fully explained my reasoning.

The isolator is to isolate the fan not control wiring

Your statement makes no sense to me

All logic says you should isolate locally

17-07-2023 3:57pm

https://www.boards.ie/discussion/comment/120863192#Comment_120863192

I will take your questions one at a time:

Q: What is your reason for stating that isolating upstream is best practice.

A: This allows someone to safely work on the control wiring as well as the fan unit itself.

Q: The isolator is to isolate the fan not control wiring

A: Where did you get this information from? I would argue that it would be more correct to say that the isolator must isolate the fan, but can also isolate the control wiring.

Q: All logic says you should isolate locally

A: The isolator can be as local to the fan as you wish. All logic tells me that it is best to design wiring to use components that are easy to obtain.

In post #7 you state "Fan above needs 4-pole fan isolation if using max/min". I agree that a 4 pole isolator would work, but how common are these for a domestic installation? Can you link to one that you think would be appropriate? Compare this to a 2 pole isolator, these are very easy to obtain.

kirk. · 17-07-2023 4:04pm

1,2 isolating control wiring is an irrelevance and unnecessary

3, good practice would be to break live conductors locally as per appliance isolation, you are guaranteed electrical isolation, fitted upstream electrical isolation is never guaranteed

Isolating upstream may introduce complexity, cabling and time to the work if using bathroom wiring and is of no benefit

It may be useful to be able to isolate 'fan only' to test wiring and troubleshoot wiring faults

Screwfix €20 , rotary isolators are commonly used in domestic installations

18-07-2023 6:46am

https://www.boards.ie/discussion/comment/120863587#Comment_120863587

That isolator is a bit ugly for a home IMHO. I think that many a customer would prefer a DP isolator in the expensive new kitchen rather than that monstrosity.

What you suggest and what I suggest will work and is compliant, each to their own. We have already agreed on this, you just need to accept that different people will tackle the same problem in different ways.

"good practice would be to break live conductors locally as per appliance isolation, you are guaranteed electrical isolation, fitted upstream electrical isolation is never guaranteed"

The part in bold is factually incorrect. An isolator will work in exactly the same way regardless of where it is fitted.

kirk. · 18-07-2023 12:21pm

https://www.boards.ie/discussion/comment/120865207#Comment_120865207

Isolator will likely be in attic

The last paragraph you are changing the subject to 'operation' of an isolator which is a different matter

I accepted 2-pole complies if wiring allows when I realized I had probably misinterpreted the rule on breaking live conductors . I have no issue with opinions or being proven wrong

However you claimed 2 pole is "best practice" and have failed to demonstrate why imo .

Anyway we'll have to agree to disagree it seems

10-10-20 · 18-07-2023 12:25pm

https://www.boards.ie/discussion/comment/120858748#Comment_120858748

I was talking about the control aspect and thinking about controlling the fan's speed using sensors. Was that not the question at hand?

kirk. · 18-07-2023 12:27pm

https://www.boards.ie/discussion/comment/120866466#Comment_120866466

Ya misunderstanding so

I mistakenly assumed switching direct

kirk. · 19-07-2023 11:33am

https://www.boards.ie/discussion/comment/120865207#Comment_120865207

Anyway leaving aside debate over best method😁 you're fundamentally correct in that there may be various ways to comply with rules and that's down to choice

I did wonder about fan isolation previously, the rules define an appliance as a current using device excluding a luminaire or an independent motor or words to that effect

Dunno is a fan an independent motor or not according to the definition. That's the problem with self education anyhow , you're better off being taught some things

switch for 2 speed inline extractor fan

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