Are you actually allowed to use a ladder to get off your high horse? doesnt look very safe to me.

It turns it off, but doesn't isolate it. banghead

Isolation is required in all poles, functional switching is provided in phase conductors only so lightswitches\unswitched spurs etc... are functional switches. Switched fused spurs\douple pole switches etc... are isolators as they isolate allpoles. (The above examples apply to single phase systems).

46790[/snapback]

DP switches usually isolate live and neutral, but not earth. So, technically NOT all poles.

I can see the logic of that, but if a circuit is wired incorrectly then you may want to isolate everything. Anyone know what the formal view is of isolation, or is it depending on the context?

As a footnote, our gas boiler has it's mains supply via a DP isolating switch. A few years ago the "Gas Board" didn't like this much, they almost got to insisting on a removeable 3-pin plug for isolation. But, recently the servicing guys have said they prefer the switch as it maintains earth. And they test everything first anyway to make sure the circuit is fine.

Ok then, for the purposes of the following live conductors are phase and neutral, excluding earth. Earth should never be switched, it doesn't get included in the term 'all poles', and non-ameteurs know this.

Isolation is switching in all live conductors, (phase and neutral), earth is to be maintained at all times and should never be switched. Doesn't matter in which context it is, that's isolation.

A single pole switch of any variety, whether it's a light switch or unswitched spur, is classed as a functional switch and is required to be fitted to phase conductors. Single pole devices should never be installed in neutral conductors. Neutral conductors should only be switched as part of a multipole isolator switching all live conductors.

Technically, alarm panels should be isolated with DP isolators. It's just convention that says not. Contactum do a DP switched fused spur with key operated switch and fuse removal for alarm panels and the like.

Edited April 4, 200521 yr by Lurch

Contactum do a DP switched fused spur with key operated switch and fuse removal for alarm panels and the like.

46810[/snapback]

Hmm, interesting, but I'm assuming its really just a 'factory assembled' product using their grid system? Dont know much about Contactum. Presumably you could make your own using MK grids, never thought of doing that.

Stu.

Edited April 4, 200521 yr by datadiffusion

Hmm, interesting, but I'm assuming its really just a 'factory assembled' product using their grid system?

46833[/snapback]

Nope, completely one off product. Designed for the job. Unforunately, the Contactum website is useless, and I'm too lazy to go and look in the contactum catalogue for the part number, maybe later.

Here we go, for a start 3467, 3469.

Edited April 4, 200521 yr by Lurch

MK do a pre assembled metal clad switched spur with a key switch, I use these for fire alarm & burgular pannels.

At the end of the day, the fact of the matter is that a switch spur should not be used for a security panel.

Unless you want to do it to BS7671, which you do, otherwise the alarm technically isn't installed to the standard of the day, technically.

Nope, completely one off product. Designed for the job. Unforunately, the Contactum website is useless, and I'm too lazy to go and look in the contactum catalogue for the part number, maybe later.

Here we go, for a start 3467, 3469.

46837[/snapback]

Your not kidding, website slow as you like and then that product isnt listed (checked both 'switched' and 'unswitched' spurs and searched just to be sure!)

Stu.

Your not kidding, website slow as you like and then that product isnt listed (checked both 'switched' and 'unswitched' spurs and searched just to be sure!)

47025[/snapback]

I could scan the proper pages in if I had the motivation! Meanwhile, here's some ropey photo's of the relevant unit! Also available in white.

Edited April 5, 200521 yr by Lurch