Isolators, switch fuses and BS7671 - understanding key selection criteria - Lewden Palazzoli

Isolators, switches and switch fuses come in all sorts of shapes, sizes, materials and ratings. In this video, we explore the key criteria referenced back to the requirements of BS7671.

Using the extensive range of Isolators and switch fuses from Lewden Palazoli, we highlight the ket features from types and current ratings to locking off and identification.

🕐 TIME STAMPS 🕕
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00:00 Isolation switches and switch fuses from Lewden
00:20 What is the difference between a switch and an isolator?
00:38 Symbol for an isolator capable of switching on load.
01:40 Switching functions in BS7671 table 537.4
02:00 Isolation, functional switching and emergency switching.
03:03 Identification of emergency isolators BS7671 - 547.3.3.5
04:16 Choosing and isolator switch.
04:29 Current capacity and load type AC21, AC22, AC23 and kW rating.
05:51 Wiring space.
08:04 Isolator enclosure options, plastic, metal and GRP.
08:55 IP ratings - IP65.
09:12 Isolation and locking off.
10:07 Interlocked covers.
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🎦 Presented by
Gary Hayers - editor eFIXX
Gordon Routledge CEng MIET - technology editor eFIXX

#efixx #morepower #bs7671

[efixx]

This video is included in the eFIXX September 2020 live feed event click the link below to win great prizes.

[karimi]

the only person who can properly explain. easy to understand! thanks a lot

[mtfpuk]

Fitted one the 125 amp ones the other day and omg it was so nice to have the room to work in them

[brianwood]

I didn't realise Lewden Palazzoli did such a wide range of Isolation Devices. I've used the smaller ones, but will in future look for the larger ones too.

[TIGREinVOLO]

Excellent explanation. Sharp, simple, exhaustive and fun! Thank you

[HereForTheMusic-ho]

I use these everyday and probably take them for granted, wouldn't have been able to put my finger on many of the regs mentioned in the video. Good information! Thanks!

[mathman]

Still believe the lever type isolators work best the rotating isolators seem less obvious and you have to look closely to see if it’s in the off position at least in an emergency situation.

[enriquedmu]

You have ventured onto John Ward territory here, making a rather boring subject enjoyable to watch. Good to know the regs on it. Thanks

[alistercarmichael]

I just refitted a MEM excel 20A fuse isolator. To provide protection for a welder on a plug/socket combo. I was surprised to see that they are still available new as they have thrown switch blades, nor do they come in Red and yellow.
Despite being a bit pokey inside they are however better built than most metal switches I've used from many manufacturers now, even at higher ratings.
What is your take on the provision of fuse protection for portable equipment. It's not something that I see implemented well or at all and expect many sparks would say a socket should be provisioned with the full rating, which is inappropriate for the load.
Eg. An inverter welder to be fused at 20A would have a 32A plug. No fuses in the welder. So semiconductor (Ag?) Ultra fast HRC fuses should protect the outlet at 20 amps. These can easily be fitted to the excel fused switch I'm using. Thus resulting in a 20amp outlet with suitable protection for the load.

Hard wired devices are easier as there is no issue with the outlet being used by another load. It's a pest installing additional fuse carriers after a big isolator, but it should be done. Especially with inverter drives. But it is something I rarely see. Even inside panels there is no suitable protection for drives and (power) electronics.
Do electricians stop at the cable protection and pass the buck to the equipment makers ?

A good subject I think.. where is the protection ?

[brad]

Brilliant and very informative! Would love to see something on switched fused isolators if possible. Thanks

[triathlontim]

With lots of solar installations, could you describe the difference between the DC and AC isolators (and why you can't simply use one type for both)? Thanks!

[garethblake]

Hi, l always look forward to watching your very informative videos even as a retired british electrician. I am presently in central American and in comparison to most british electrical installation the local electrical installation leave a lot to be desired in fact quite scary at times! Keep up the good work and stay safe.

[raychambers]

Always used MEM switchgear the only I didn't like about them was insulators were a bit fragile and sometimes broke in transit.

[NoName-vlgr]

I'm an anomaly, I don't know why YouTube recommended your channel lol

[شبحالابيض-غظ]

Thank you very much.
What country are you in?
I am from Iraq.

[mlard]

What kind of isolator do you recommend when using on a house (meter connection to the emergency switch, to the panel board) installation?

AS THE ➡️ EMERGENCY SWITCH

[acelectricalsecurity]

Never knew some of those regs, very informative. You missed out price, and they are one of the cheapest to get hold of, I always use the 100amp switch fuses, one thing I would say, the connections are quite low down, and when you have a 25mm swa to connect it's a bit of a fight, maybe a slightly bigger enclosure would be an upgrade

[MrWHITTERS]

Evening Chaps great video. I'm currently working on an industrial design project which has a number of Fuse Distribution Boards in the same room. Board supplying sub Boards. I would like to install Isolators local to these sub boards to provide a suitable and safe means of Isolation. The client say that Isolators at the sub boards are not required as the up stream board is in the same room and they can just pull the upstream fuse to provide Isolation. Surely this is not the right approach? Where do fuses sit with "Isolation" "Em Isolation" or Functional Switching"? My biggest concern, note that this will be a brand new installation, is there is a risk of the fuses popping in someone's hand when inserted or arching when they struggle pulling it after many years, whilst doing this activity on load.

[pakcom-vlkd]

Can you fit a isolator bigger than required? say if I only needed 40amps, can I use a 100amp?

[mtfpuk]

Should a 9ne on whims regs for water company's qnd the gland packs we have to use as jist not q standed cw pack