electricalforum.nz

I was recently talking to someone at a trade show regarding having to have a isolator for a hot water cylinder under the current standards.
They had the appropriate page from AS/NZS:3000 printed out which also included the fact that the isolator can be on the switchboard, in my opinion this would be covered by a MCB, however they made the comment that not all MCB's are classed as isolators.

This is the first time that I have heard that theory so thought that I would ask on here about it on here

see AS/NZS 3000:2007 +A1 +A2n clause 2.3.2.2.2.

Nathan, Circuit breakers are suitable for isolation as they will all comply with AS/NZS60898.1 (AKA IEC 60898-1).
They should also be marked with the symbol in the clause that Pluto indicated, which confirms they are suitable for isolation.

Thanks guys I thought that was the case, they did mention to me that not all breakers were labeled with 60898 and those ones were not able to be used as isolators, however from what Doug said below, any currently being sold have to comply with that so its a non issue.

It was a combined trade show (sparkies, builders, and plumbers) and they had printed out a copy of 4.8.2.3 to "prove" that we need there new hot water kit with a isolating switch on every cylinder we install, so im not very impressed with their tactics.

I do feel sorry for them in a way though, they did design and build a new switch purely to comply with the new 3000:2018 version and then got stuck with them but its not the way to sell them.

DougP's right that all mcbs available through NZ market channels are suitable as isolating switches.
They meet all the requirements for isolation devices in that clause cited by Pluto.
They all have a switching function; they all have manual operation, and they can all be locked in the "open" position.

Mcbs are DMRAs requiring SDoC [ESR 83] and also DHRAs requiring approval by Worksafe [ESR 84].
There's no chance of getting approval for an mcb that doesn't comply with the standard.
And providing the isolation function is a requirement of the Standard.
but being labelled with the "switch disconnector" symbol isn't.

true those who bright switch kits to market, or changed the kits they were offering, based in the "new"rule in 2018 edition may not be selling as many as they expected.
That's down to (excessive?) delays in getting Schedules 2 7 4 if the ESRs amended to update the citations.
But while it's not yet mandatory to have local isolation, good practice would be to adopt this practice now.
Especially for HWCs with multiple supplies (though the kits I've seen don't cater for that).