Sub-Main SWA Circuit and the Connections in our Wylex DSF60M Switch-Disconnector Fuse (Switch Fuse)
Students training aid for the connections in our 60 amp Wylex switch fuse and the need to connect the earth bar to the incoming earthing conductor.
There are several different ways to earth the exposed conductive part via the earth bar. I allowed my learners to select the way in which they want to do so. It was tricky to take the earthing conductor via the earth bar because lack of room and bending radius of this conductor. I like the SWA cpc conductor to be terminated in the top of the isolator and a fly lead from the same position down to the earth bar. Video was produced to highlight the need to earth the metal enclosure. Thanks Gaz
Understand and Carry Out Terminations and Connections of Conductors 5357 107.
Videos are training aids for City and Guilds (C and G) and EAL courses Level 1, 2, 3 plus AM2, AM2S and AM2E.
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Simply explained, easy for the learners to grasp. Provided they want to learn, Great video as always Gaz ❤️👍👍👍
Thanks 👍🏻
Great video mate🛠
I think your brilliant only if i had you has my teacher once again Excellent
Thanks for the support Gaz
Good video. Wylex need to rethink their design of the switch-fuse really. A factory link between the earths should be in place to avoid dramas down the line!
Hi. Totally agree 👍 thanks for commenting and watching Gaz
Excellent video Gaz. Want to know something ironic? We've a mains change coming up that requires the exact same switch fuse unit in your demo to be fitted. My 1st year apprentice will be tasked with glanding off a 3 core 16mm2 SWA and run in a loft about 8M away to a split load Wylex dual RCD CU. I will see if he figures this method of ensuring earth continuity by means of the cpc link to ensure both the enclosure and final circuit continuity are achieved.
The sub main can it be part t&e for going under the floor in a domestic dwelling but joined in a wiska box with swa once you go outside to an out building. Also can you instead of the fuse enclosure not just say have on mcb or rcbo on the supply side?
Is there a reason for the use of metal enclosures? Because if there is a short or something and the box becomes conductive then it needs earthing, but having it made of metal means it is can be a hazard to the people touching it if there is a fault
Are the fuses that fit this the 22.23mm fuses thanks
I have a meter/consumer unit located in the hallway of my house. I want to move this consumer unit as part of a rewire 7 metres from the metre running cables under the house. What cable is best used to go back to the meter from the new consumer unit? Should it be the method used in this video or is there a more simple way and one that doesnt involve using SWA cables that are hard to work with?
Thank you for sharing such wonderful knowledge, but can you design ATS connection for multi Storage Residential building under Single phase power supply please?
Do you "have" to use a banjo and fly lead to earth the armouring if the Enclosure is metal and earthed and not a removable glanding plate?
Thanks for taking the time to make these videos. Just a quick question. Why not link the (presumably larger) incoming earth cable to the earth terminal in the case then to the switch unit, rather than using the the outgoing cpc?
Hi. Yep you can but the room is limited around the earth bar and if you had a 16mm earthing conductor it would have to tight of a bend. I let my learners decide how to solve the problem. The best one for me was to take the SWA cpc into the top earth terminal and a fly lead from the same position back down to the earth bar... thanks for paying attention and your top question Gaz
What size is that cable tray
Hi, could you do a video demonstrating the removal of a service fuse, with permission of course but I thought you could use the demo rig to show pulling a fuse and showing how to upgrade from old cloth meter tails, the way I do this so long as they are 16mm2 consumer tails is to cut them short to around 300mm from the meter then two single pole 100 amp Henley blocks connecting up to the new 25mm2 this is so when all of the work is done the supply authority can come and cut meter seal and put out new 25mm into it (I leave some slack for this)
What a great idea... time is not my friend at the moment as all my learners are doing exams... see what I can do in the coming months thanks Gaz 👍
I’ve got some 6mm 3 core swa and some 3mm stainless steel catenary wire, for attaching the swa to the wire whats the usual procedure? No spiral of the cable simply attach it to the wire with UV resistant zip ties? Or is there a more suitable fastener? Run is about 10 meters
Hi. You may want to consider using some metallic cable ties. Thanks for watching GSH Electrical 👍
Does this Wylex unit use a 57x22.2mm fuse size? This is the size all the switch fuses I've seen use, but I can't find one in 20A, lowest I've found is 32A. Interested to get to the bottom of this as I'm a bit confused!
Hi Gaz. You have linked the earth bar to the earthing ring of the outgoing SWA gland with a piece of earth wire, which makes perfect sense to me. Do you know why some electricians don't do this? What do the regulations say about this topic? Thanks Jozef
Jozef Kois thanks for commenting... great question and in short I don’t have an answer. In my experience testing an SWA sub-main and proving polarity this method works best for me and my learners 🦾. Thanks Gaz
@@GSHElectrical Thanks for your reply Gaz, much appreciated. I am always linking the earth ring to the earth bar. However I have received criticism from my superiors on numerous occasions for doing this, claiming that I was over doing things. It would be great to have clarity in this.
Is there a reason why you take the outgoing earth connection to the earth tag, rather than the incoming earth? Another excellent video by the way.
I haven’t watched this video back but it’s all about removing the parallel Earth path’s created by the steel of the SWA cable 👍. Thanks again for watching. Gaz
So the earth path is still complete even if the power is isolated.
why De-neutralise the black wire ?
Gaz, what dimensions are your testing boards? Looking to make one at home
Great question... PASS 🤣🤣🤣
GSH Electrical be a love and find out for us? It'll be in the teaching notes from C&G for 2365 so afaik not publically veiwable.....walled garden, joys!
Hi would this fall under the minor work’s certificate?
so is that wylex switch a sub main?
Hi. Yes Wylex 👍
@@GSHElectrical thanks what is the reason to install one of these next too a meter? if the tails are too long and any other reasons?
Hi Gaz. I’ve just mage to comment on your videos as I’m always busy trying to complete my level two/three. However, your videos are a true inspiration for anyone who’s studying to be an electrician. Very clear and easy to understand. I’m currently studying the 17th exam and find the book to be a little challenging on understanding how to search for certain topics. Any hints and tips you could provide please? Lincoln
Hi. Thanks for the positive comments. We have our learners download an app for the 17th that generates question I think the full app is £5 and the free one only allows limited access. We use the app alongside a CD book I got of EBay. Thanks hope this helps Gaz
Why do we use cartridge fuses instead of MCBs? That Wylex switch fuse looks a lot more expensive than a generic 2-way metal consumer unit with main switch and one MCB. CPC do them for £20 or so. Resetting an MCB is much easier than ordering a new fuse and making sure the end user doesn't decide to increase the fuse rating to a value which no longer protects the cable. Nice video by the way.
Hi. The assessment requires a switch fuse to be used and yes they are expensive. Always good for learners to see different kit in my workshop as well as different overcurrent protective devices. Thanks for watching Gaz
So when should I choose to use a cartridge fuse like this instead of a £1.50 MCB? I qualified seven years ago and haven't thought about it much till now. I always seek to avoid unnecessary expense for the customer, but am I compromising safety in some way? Do we use cartridge fuses to stop the user from reconnecting the circuit after an overcurrent event? Isn't that when we find tin foil and paperclips?
Hi. As the designer you can select the means of isolation/overcurrent you wish. This is a sub-main circuit tailed directly in to supply and can be rated as high as 100 amps... The SWA would be say 16mm in the real world and fuse at 60 amps feeding say a flat...I am currently at a dancing festival so cannot check but don’t think you can get single phase circuit breakers at 60 amps, 80 amps or 100 amps. However if this was a sub-main to a shed you can come out of the consumers unit to the new board. Hope this helps and thanks for watching Gaz
Apologies, hope I didn't interrupt the festival :-) I'll see if I can look on a discussion board somewhere as I appreciate you'll be busy with college duties tomorrow. Here are my current thoughts in case you think they bring up something worth discussing further: Fig. 3A4 in Appendix 3 (my book is the green pre-amendment BS7671:2008). The chart shows disconnection times for MCBs which go up to 63A, 80A, 100A and even 125A. I have a 63A in my box of spares, but never seen the higher ones. I remember doing a side-by-side comparison of fuses and MCBs many years ago. I recall one advantage is that the compact size of a cartridge fuse means it will fit into an enclosure such as a 13A plug. Space isn't a consideration for this sub-main obviously. An MCB can be used for a 125A circuit, and they can safely interrupt 6kA and 10kA. Contact separation satisfies the requirements for isolation of the line conductor. As a designer I should know some examples of when a cartridge fuse might be a better alternative to an MCB. It's likely I've missed something.
Hi. Unsure if those breakers would fit in a domestic consumer unit. The job in my video is set out by our awarding body and requires as switch fuse to feed a consumer unit via a SWA cable. Thanks for your interest and detailed response all the best GSH Electrical
Wylex could have designed this switch fuse enclosure better than this, why not get rid of the incoming and outgoing earth terminals and just put a solid MET at the top of the enclosure as they do with they consumer units.
Hi... totally agree... someone is going to missed earthing the enclosure... we paid £80 each for them so we cannot change them anytime soon lol.