| Ask The Trades | |
|
https://www.askthetrades.co.uk/cgi-bin/yabb/YaBB.pl
DIY Forum >> Electrical Questions >> 3 pole fan isolating switch https://www.askthetrades.co.uk/cgi-bin/yabb/YaBB.pl?num=1107263245 Message started by braychurchmouse on Feb 1st, 2005, 1:07pm |
|
|
Title: 3 pole fan isolating switch Post by braychurchmouse on Feb 1st, 2005, 1:07pm Hi, could anybody point me to Regulations (in simple terms) re use of this. ie why is it 3 pole...does this mean it disconnects earth :o . For bathroom use I was just planning to put a two pole isolating switch OUTSIDE bathroom, but my local TLC says this 3 pole switch should be INSIDE bathroom ...and not to bother anyway unless its new build. I tried Googling "BS 3676" "BS EN 60947-3" but I just get list of people making or selling the switch. Also tried http://www.iee.org/Publish/WireRegs/bs7671.cfm but got myself lost!! The Crabtree catalog says "Provides local isolation of fans with or without timers whilst the rest of the circuit remains live. Enables repair or routine maintenance of fans. 240V only.For full details of compliance with BS EN 60947-3 see Technical Data page 107. " But p107 is not much help. :( Thanks in advance to all responders. |
|
Title: Re: 3 pole fan isolating switch Post by L.Spark on Feb 1st, 2005, 2:00pm wrote on Feb 1st, 2005, 1:07pm:
Firstly I don't believe this is a requirement of BS 7671, more a new requirement that NICEIC have set We never disconnect the earth, earth always remains connected, the 3-poles are for a permanent live, a switched live, and a neutral Quote:
3-Pole isolators are for fan's with a timer usually, the isolator switch should be located outside the bathroom e.g. above door, I don't think you can put one inside the bathroom and still comply with BS7671 bathroom zones Quote:
Here's a link to a 3-pole fan isolater http://www.screwfix.com/app/sfd/cat/pro.jsp?ts=66284&id=12319 Quote:
Yep, for local isolation to conduct maintenance or repair, usually for use with timers, but use them for what you like |
|
Title: Re: 3 pole fan isolating switch Post by braychurchmouse on Feb 2nd, 2005, 12:13am Thanks for the comprehensive reply L Spark. That really clears things up for me. :-) :) |
|
Title: Re: 3 pole fan isolating switch Post by buckholst on Feb 12th, 2005, 8:59pm Just to clarify two poles of the switch are used to disconnect the live feed from the lighting circuit and the neutral feed the 3rd pole is used to disconnect the non switched live required for either run on or humidistat controls (if the fan has them). The earth conductor cpc should never be switched. |
|
Title: Re: 3 pole fan isolating switch Post by plugwash on Feb 13th, 2005, 12:17am the only time an earth should be switched is when using a supply changeover switch with supplies whose earthing systems must not be connected. in this case it must be ensured by the design of the changeover switch that earth breaks last and mates first. |
|
Title: Re: 3 pole fan isolating switch Post by buckholst on Feb 14th, 2005, 11:41am Good point well made, but an unlikely scenario for a bathroom? :) Cheers. |
|
Title: Re: 3 pole fan isolating switch Post by L.Spark on Feb 14th, 2005, 4:07pm lol, yea PW does that, but there's no harm knowing the requirements for nuclear power station switching for you're home sweet home :D |
|
Ask The Trades » Powered by YaBB 2.3! YaBB © 2000-2008. All Rights Reserved. |