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we have a mains supply 400A from a switch room which is fed from a switch fuse to a old Bill red spot board which is approx 80M away,we are removing the fuse board and installing a bus bar chamber in its place,do we need to install another switch fuse isolator below the bus bar chamber or is the one in the switch room adequate as long as we label the bus bar where to isolate
martin
 
Provided the switch-fuse disconnector can be locked off in the switch room then it should be okay. Personally I would install an Eaton chamber which allows the mounting of a Glasgow switch-fuse with a linking kit to connect to the chamber.
 
Do you rate the Eaton Glasgow chamber and fused-switches as better than Schneider Square D equivalents?
 
The last Glasgow switch I saw was made decades ago (in Glasgow)!

More recently folk on here suggested the Square D option so I got a SQB1003K (100A TPN) for a new project and will be getting another two to complete it hopefully soon. They seem well made, are cheaper than the (seemingly identical) Merlin model, and had two features I really like:
  • Double switched so both ends of fuses are fully isolated (i.e. you can use it top or bottom fed, or in our case with a potential back-feed of leakage current from several UPS).
  • The safety covers over the terminals go to the box edges, so if changing a fuse you don't risk dropping it or a nut, etc, and them ending up in your busbar chamber.
Still waiting for our sparky to de-furlough to get it fitted at the site, but that aspect is not really under our control.
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One thing is they are quite compact (rather like the Glasgow ones) so if you have big SWA then you are more likely to need a spreader box than some of the others that are in bigger boxes to begin with.
 
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I suppose it was what I was brought up with, the era in which I started when it came to distribution you only considered MEM.
 
The last place I worked at was all Glasgow / MEM fused stuff put in early 70s, lasted without a hint of trouble until it was rewired around a decade ago and they went Square D boards.

Unfortunately a few folk have reported the quality of the MEM / Glasgow stuff has suffered in recent years, but I have no first-hand experience to say.
 
More recently folk on here suggested the Square D option so I got a SQB1003K (100A TPN) for a new project and will be getting another two to complete it hopefully soon. They seem well made, are cheaper than the (seemingly identical) Merlin model, and had two features I really like:
  • Double switched so both ends of fuses are fully isolated (i.e. you can use it top or bottom fed, or in our case with a potential back-feed of leakage current from several UPS).
  • The safety covers over the terminals go to the box edges, so if changing a fuse you don't risk dropping it or a nut, etc, and them ending up in your busbar chamber.

Any fused switch will withdraw the fuse completely, that's the difference from a switch-fuse.

Yes the Square D and Merlin Gerin are identical apart from the paint colour and the price, both brands are part of the schneider group now.
The reason given by the schneider rep for why the Merlin Gerin is more expensive was 'because specifiers want MG so we can charge more for it'

The same goes for Acti 9 RCBO's versus IKQ RCBO's, exactly the same device but with different screen printing (and a busbar clip)
 
Any fused switch will withdraw the fuse completely, that's the difference from a switch-fuse.
That was what I assumed, but it seems that terminology is not used consistently. Take Hager, for example, on page 86 of the catalogue here:

They define "Switch Disconnector Fuse" as the double-break style, but "Fuse Switch Disconnector" as the single break of moving-fuse type. Of course when you look at their range on page 40 they are called "Fuse Combination Switches " which is a term not mentioned anywhere in the technical details page! Helpful, not...
 

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