connect fan with no earth to RCD

[Hel]

Hi,

I am trying to replace an old bathroom fan with a new Airflow iCON30. The old fan was powered through a spur from lighting circuit. Only live and neutral wires were connected, the earth wire was not (the lighting cable has unsheathed wire in the middle and this wire was cut). The new fan requires a 3A fuse and also I have been told that 30mA RCD should be installed.

So I was thinking to install RCD protected fused connection unit (http://www.alertelectrical.com/prod/336/rcd-spur-connection-unit) between the fan and the spur from lighting circuit. My problem is that RCD requires 3 wires to be connected : live, neutral and earth. My fan is double insulated and has a module switch installed inside, so that it operates only using live and neutral wires.

My question is how to wire my fan that requires 2 wires (live and neutral) to RCD that requires 3 wires (live, neutral, earth) to spur from lighting circuit (which i presume is connected to earth)??

Please help!!!

Thanks

 

[ban-all-sheds]

Use twin and earth, connect the earths at the RCD but not at the fan.

BUT - presuming the earths are connected all the way back to the CU is unwise - do you really want to trust your life to someone like the person who installed the original fan? OK - that is probably a bit dramatic, but the point is you cannot be sure that the earth is continuous back to the CU, and you need to be.

It's easy enough to check with the right equipment - any electrician will be able to do it for you.

You should also read this: //www.diynot.com/wiki/electrics:part-p

 

[ricicle]

Last things first, only the L + N are connected through an RCD.

I take it from your post the wiring is existing ?

 

[Hel]

Hi,

Thanks for replying so quickly!

The existing wiring is a spur from lighting cicruit that is connected to the old fan. RCD is a new addition that I would like to install.

Maybe it makes sense to check if the spur from lighting has an earth and then connect L, N, E from it to L, N, E in RCD and then have a wire from RCD with N,L,E connected at RCD output to the fan and connect only L and N at the fan??

 

[ban-all-sheds]

It seems that some people still do not grasp the concept that telling someone asking for advice that what I have written is wrong, not because it is but because they have taken a personal dislike to me, is damaging and dangerous and in no way whatsoever of value or benefit to the forum.

Use twin and earth, connect the earths at the RCD but not at the fan.

Would any of the people who gave my post a thumbs down please explain in what way that advice is wrong.

BUT - presuming the earths are connected all the way back to the CU is unwise - do you really want to trust your life to someone like the person who installed the original fan? OK - that is probably a bit dramatic, but the point is you cannot be sure that the earth is continuous back to the CU, and you need to be.

Would any of the people who gave my post a thumbs down please explain in what way that advice is wrong.

It's easy enough to check with the right equipment - any electrician will be able to do it for you.

Would any of the people who gave my post a thumbs down please explain in what way that advice is wrong.

You should also read this: //www.diynot.com/wiki/electrics:part-p[/QUOTE]
Would any of the people who gave my post a thumbs down please explain in what way that advice is wrong.


Hel - if you see no proper responses to this post (which you won't) and/or if you see more negative marks for the original, and negative marks for this one (which you probably will) you may safely assume that there isn't anything wrong with anything I wrote, and that the negative ratings it got were because I wrote it and some people here have taken a personal dislike to me for reasons which are completely unrelated to this topic and are nothing to do with what I wrote here.

If you believe that you should be better served by people here when you're looking for advice than to have your answers given misleading ratings by them because they are engaging in a personal vendetta then all I can suggest is that you complain to the moderators/admin and/or look for another site to get advice which won't get trashed by a bunch of childish idiots.

 

[Hel]

Ban-all-sheds,

Thank you for the reply. I think that I will follow your advice.

I will check if lighting circuit has earth. If it does, I will connect L,N,E from it to RCD and then L,N,E from RCD, but will only connect L,N at the fan.

I am really new to this forum, so I am not aware of any current affairs here.

Thanks again for the advice!

 

[ombos]

I have not read the full repies so apologies if someone as mentioned this point: Fit a RCBO to the lighting circuit at the CU and pick an earth up from the said lighting circuit at any junction point for your fan, in my books sorted and get a part p person to issue a minor works cert (if you really want to).

 

[ban-all-sheds]

I will check if lighting circuit has earth.

How?

Just looking won't tell you for sure.[/quote]

 

[ban-all-sheds]

in my books sorted

How will he know that the earth connection is any good?

How will he know what the fault-loop impedance of the circuit is?

How will he know that the RCBO works properly?

and get a part p person to issue a minor works cert (if you really want to).

If he does all the things you suggest then there is no way he'd be able to get any sort of certificate for it from an electrician, and no way he'd get the electrician to notify it as his work.

 

[ombos]

Heres an easy method if you've no continuity tester) fit the RCBO to your CU and ensure that you switch the phase ( the switch to on your RCBO) to off, please please ensure its off!!!!!! find the junction box your going to take your earth from and remove the cover, please use some teating device such as a simple fluke tester and ensure that the phase is not live. Bridge the N and E and your RCBO should trip. If it does not you look like running a new earth cable in from your CU. Seen this so many times, lighting circuits with no earth, if you dont have one (an earth) it maybe telling you thats its time for a full rewire anyway, get advice.

 

[bernardgreen]

such as a simple fluke tester and ensure that the phase is not live.

Simple testing device. Define what you consider is the minimum to test and ensure the phase is not live ?

Bridge the N and E

I would suggest that before doing that you ensure with reliable test equipment that the neutral is also not live.

and your RCBO should trip.

but it might not trip even if the installation is OK. It might trip if the installation is NOT correct.

If the the earth wire that you short the neutral to has no connection to earth ( ie faulty installation ) then any current from a fault involving that earth wire will flow through the RCBO's neutral and trip the RCBO

if you dont have one (an earth) it maybe telling you thats its time for a full rewire anyway, get advice.

That is sensible advice

 

[ban-all-sheds]

How will he know that the earth connection is any good?

How will he know what the fault-loop impedance of the circuit is?

How will he know that the RCBO works properly?

Would the person who voted my post down, or indeed anyone minded to do so in the future, please explain why those were questions that should not have been asked?

If he does all the things you suggest then there is no way he'd be able to get any sort of certificate for it from an electrician, and no way he'd get the electrician to notify it as his work.

Would the person who voted my post down, or indeed anyone minded to do so in the future, please explain in what way that was incorrect?

 

[holmslaw]

..

 

[ombos]

Stop right there me duck, I'm not on trail here, You might as well just say to every blog on here get a part p person to inspect your circuit, which is correct you should do that and I'm surprised that a forum of this nature exist, but all I'm doing is giving my 30 years of qualified advice to someone else that you assume has basic knowledge to be able to conduct his/hers work safely. How did we go on without testing equipment I will never know, but now its the regs so like I said just close this forum down and set a new one up called part p qualified persons banter forum, I can remember being told that I had to do my level 3 NVQ as my old C&G 1&2 were not as good, that was a load of bull too, what a entire waster of time. So like I said will you just reply to all blogs and say get a person in to check your system, we can all pull apart what another person says but this is a blog and not college and I use some old methods and yes you correct re the test but how many times have you known them to occur??? hang on what if theres a N feed back from the mains, we could go on for ever, thats why theres so many methods of lighting circuits, so please dont ask me to justify my advice, they can take it or not simple and the same goes for yours

 

[ban-all-sheds]

BAS could you alter your settings so that your poorly rated posts are not hidden. Its a PITA having to click on them to open them.

Thank you in anticipation.

It's your setting, not mine.