2 Gang Dimmer Switch - Safe Isolation Procedure

i'm at my mum's house today and she requires  a dimmer switch to be changed so that's a job   for a son so income son but we're gonna do  the safe isolation procedure in this video   now we've done it before a a light and we've done  a safe isolation procedure there and we do that   at college and a load such as a consumer unit  or a three phase isolator but this is a light   switch i thought it'd be a little bit different  i've seen permission of effectively my mother   that i can turn off the supply and believe it or  not there isn't even wi-fi here so i'm not going   to knock anything off that's going to cause any  grief for anyone else so she'll give me permission   to do the job and now i'm at the consumer unit  which is under the stairs and maybe that's a   different video we can look at whether a plastic  consuming being under a stairs is a good idea or   not but we'll save that for a different video  so i now need to investigate which circuit to   turn it off now i'm hoping the electrician  that maybe installed this some 18 years ago   may be fully labeled the consumer unit and that  would be really handy so as i drop it down we can   see a full row of stickers here and hopefully  they're correct there wasn't an additional   alarm circuit added by somebody i don't know who  that was but it certainly wasn't the person that   installed the consumer unit and we've got a nice  sticker here that says downstairs lighting circuit   you'll note that it's not on an RCD when this  was installed all those years ago it wasn't a   requirement again that's a conversation for a  different video so hopefully when i turn this   one off the light and circuit in the living area  will go off now i've left them on so obviously   when i drop the breaker out i can see that they've  gone off and that's a first indicating point to   me that maybe i've selected the correct circuit  if this was a really heavy drawing current load   i probably wouldn't want to be switching that  off at the breaker maybe you'd look for a neon   indicator or some other clue that that circuit  has been isolated but for this lighting circuit   i'm quite happy to turn it off on load so in other  words the light in the lounge areas are currently   on and i turn it off the other issue i've got is  obviously i'm under the stairs and you would think   the lighting circuit downstairs would also include  the light here in this area so we're likely to go   dark unless the electricians put it on a different  circuit so let's find out by turning off hopefully   what we believe is the correct six amp type  B circuit breaker for the lighting circuit   right now the light in my area is still on so  that would suggest that you're thinking oh maybe   i've chosen the wrong lighting circuit because  logically you expect the light in this area to go   off however the real clever electrician  that wired the circuit in here actually   wired it off the upstairs lighting circuit so  in the event of losing the downstairs lighting   okay the light in here which would help obviously  you re-energize the circuit will actually be   illuminated so that's one way of getting around a  problem that could be caused by losing the power   another clever thing that is also done which means  it would work regardless of the power going off   it's also an emergency light fitting as well but  it covers it doesn't if the emergency element   had packed up over time you've still got it on  upstairs lighting circuit the downstairs one   in the area near the consumer unit so it just  requires us now to lock this off before leaving   the area now the temptation isn't it to go rushing  into the living area just to see those lights are   off but we're going to do this process correctly  that means that even if we've got the wrong   circuit we're going to secure the isolation okay  we're going to put the lock in place and the sign   before leaving this area and obviously checking  to see if those lights have gone off so i've got   my safe isolation kit out i've got my lock and key  i've got my locking off device and i've got my tag   and you'll notice here there is a QR code this  is because this is something i give away a part   of my eFIXX YouTube channel if you haven't already  started following that i recommend you do and it's   got a brilliant website efixx.co.uk with loads  of free learning packages on there and this QR   code will send you through to the free learning  package on safe isolation meaning that when you   complete that training package takes less than an  hour you get a certificate which is fantastic to   go in your record of achievement whether you be an  apprentice or whether you be a full-time learner   trying to get a job in the electrical industry  and on the know how page where all of these free   training packages sit there's over 20 that you  can tackle imagine going for a new interview   for a new job or a promotion within a company and  you can show all these additional certifications   that you've got that could be a real winner to  you so we're going to use this in order to lock   off the circuit i need to wind this back allowing  for the breaker element here to go inside here   so we're going to wind this back let's wind  that one out and then we're going to lay it   on top of the circuit breaker and then all we do  then is wind it back down to clamp on top of it   once we've got it firmly clamped into position  we'll just roll it out of the way so we can insert   our sign and a locking off device so that's nice  and tight i can't pull it off i pull down the bar   right there so that's now in place but somebody  could obviously unwind this so we must make sure   we secure our isolation so i take my padlock  and my sign and just bring it through here   it's quite small these are even though we're  giving them away probably could have done with   a little bit of a bigger padlock to take out my  key and then i just need to hook that into there   and close up my device there we go we locked it  into position so we've got our locking device off   on the circuit we think it is we've got the key  that we're going to keep in our hand we're going   to take it with us we don't leave it anywhere  around this area we're gonna need to keep this   with us and we've got a sign and if we had to  we could add some additional information on here   but we're not going to for this one so that's  locked securely into place key with me that's   going to see if the lights are turned off so the  lights in the living area now have gone off but   it doesn't mean that actually we've isolated the  correct circuit something else could have gone on   so we're still going to presume that the circuit  could be live and all the necessary precautions   to prove at the light switch that this circuit  is isolated so the dimmer can be changed so i'm   going to take off the dimmer that needs to replace  him again still be careful because obviously if   it is still alive we think it isn't but we're  only presuming it isn't so we're going to be   very careful when we're pulling things back off  the wall obviously you don't want conductors to   fly out and if they do certainly don't touch them  until you've proved that the circuit is isolated   and as we look in here maybe from previous study  programs we can work out that this is actually   feeding the switch so you can see the neutrals  there at the back they're in old cable colours   pre 2004 so the neutral is black the supply  has been taken down to the light switch   which makes logical sense because obviously  they're fancy light fittings in other words   probably not got a lot of room behind  them in order to make those connections   so we're going to need to prove in here that this  is actually isolated and dead before changing   the dimmer so i've got my approved voltage  indicator and proving unit that i need to   check it on a known supply or a proven unit before  i start so i'm going to use my voltage indicator   here to prove that it's actually correct we've  covered GS38 many times on the channel before   and if you're unfamiliar with it i'll leave a  link for that in the description as well so i'm   going to prove these are working correctly with my  proven unit i'll push them into the holes like so   and we can see off off limit or off range and all  my lamps are eliminated on the voltage indicator   okay we're happy that we're ready to use  this so we've got to prove it works first   and then we're going to use it and again we're  going to prove it at the end of the process as   well so i'm going to prove them to the least  dangerous conductor first which is my CPC   and i'm going to probe onto the line connection  now this is the one that's linked from here   to the other side so i'm presuming that's  the common or permanent line coming in   and it's linked to the other side of the two  gang dimmer so i'm going to go on to that next   and we've got zero volts okay so we come  off the line and then we're going to go   on to this one here which is the switching line  you've got a beep on the machine but zero volts   okay so we come off that one again now we're  going to turn it round again being very careful   you don't pull any conductors out we've got  two connections here as well we've got the   the common loop coming through but we're  going to test it as well so we go on to there   and again no voltages and onto this one here  again no volt so off we come so that's tested   between the circuit protective conductor and  the line connections within the light switch   we don't know which one's permanent line but we're  presuming we know what it is that's still not good   enough we've checked all of those connections none  of them show a voltage on our instrument next i'm   going to check between the CPC and neutral  so if we come into here a little connector   block and i can just push firmly into there and  we've got zero volts so let's just show it there   we've got that beep connection that's because  of the earthing arrangement system we've got   here but there is zero volts then we come off  our neutral and now we're going to test between   our neutral and the line connection so  we're going on the least dangerous one first   which is our neutral connection just there firmly  in and i'll go around again so no volts no volts   around to here onto the switch again  we've got that beep we've got no volts and   last but not least our final connection there and  then we're off our line connections and then we   come off our neutral so that's us gone round all  the connections in here so between our neutrals   our lines our CPCs and neutrals and our CPC online  connections but we're not finished yet it could   have been that our instrument had failed us okay  could have packed up in some way so we need to   prove this now is still functional at the end of  the test so simply bring our proven unit back in   and we check again and we can see we go off the  off the limit or off the range on the instrument   and there we go we've proved our voltage indicator  again so we've isolated the consumer units i've   locked it off we've proved it here at the switch  we're going to work on there is no voltage present   and therefore we're happy now that we've proved  our test instrument at the final stage that we   can start changing this dimmer switch so if you  want to see how i changed that to gang dimmer   switch for a new one and the thinking behind why  i had to change it check out the video just there

Channel: GSH Electrical

Views: 15,041

Keywords: Safe isolation, Safe isolation of the lighting circuit, Safe isolation at a light switch, GS38 voltage indicator, Proving unit, Proving a circuit is dead, Proving a circuit is isolated, Safe isolation procedure, How to isolated a lighting circuit, How to lock off an MCB

Id: BEBTGGbBHjo

Length: 9min 30sec (570 seconds)

Published: Sun Sep 04 2022