Do Isolation Switches require being lockable?

This includes types of overcurrent, Short Circuit and RCD protection
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JamieP
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Do Isolation Switches require being lockable?

Post by JamieP »

I just had my mind blown by the fact that I was always told and always believed that part of being an isolation switch was being lockable

Looking over 2.3.2.2 for devices for isolation I can't really find anything to back this up

Is this simply not a requirement?

I can see it specifies a lockable device under 4.19 with further makes me feel that it's not actually a requirement of isolation devices
JamieP
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Re: Do Isolation Switches require being lockable?

Post by JamieP »

Noticed this just before
Screenshot_20200513-191619_Drive.jpg
Is maybe this what was being referred to? Still I always thought it was part of the isolation device standards, maybe it's just a requirement of 3000
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DougP
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Re: Do Isolation Switches require being lockable?

Post by DougP »

I'm not sure what you're asking? You've circled the part that says that a switching device must be able to be locked. That paragraph is part of 2.3.2.2.1
A circuit breaker is a switching device and a device for isolation, but not all switching devices are. Some switching devices are just for functional switching.

Also for mechanical maintenance 2.3.6.1, A/C units 4.19, grid connect inverters etc, the switching device must be able to be locked.
JamieP
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Re: Do Isolation Switches require being lockable?

Post by JamieP »

Sorry, it's a bit all over the place

It wasn't until slightly later I saw that other clause, at first I couldn't find the information I was looking for

I just always thought the term lockable was used but maybe I was confusing with how lockable was used in 4.19 etc

Like you said I think I answered my own question
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Re: Do Isolation Switches require being lockable?

Post by AlecK »

Yes, not all switching devices are isolation devices.
Similarly not all devices for isolation are switches.

I's unfortunate that many of the references in Standards to "isolating switch" add the word 'lockable".
it's intended to reinforce the message; but what it actually does is make people believe that if the word 'lockable" isn't there then it's not a requirement - despite 2.3.2.2.1 clearly saying it is.

I believe a better approach is to say "an isolating switch complying with 2.3.2.2"
that way readers get pointed to ALL of the requirements instead of having only one of them emphasised.
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Re: Do Isolation Switches require being lockable?

Post by JamieP »

That's what I thought, my initial knowledge was that every switching device for isolation must be lockable (able to be secured in the open position) but seeing it as an additional term causes confusing when it's already part of what an isolation switch is and then when I couldn't see the information to back it up under the initial list of items I second guessed myself

It's amazing how much terms like these get used incorrectly in our industry, much like earthing and bonding. It causes huge confusion for those who are learning and often hard habits to get out of

Do you know how the term started getting mixed up? I believe in some past Regs I saw the term isolation used potentially for functional switches but could possibly be wrong, can't quite remember
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