Online assistance for electrical trade people in New Zealand and Australia Login  |  Register  |   Forgot Password
Assistance for electrical trade people
 

 

 

 


Click here to send Forum Admin a pdf document for publication on this Topic

Documents must be less than 200k in pdf format

Posted By Topic: Hotwater Isolator

Sam1234
Aug 27 2019 07:01

Is there a rule change with regards to domestic hotwater cylinders now needing to have lockable isolators?
Thanks
   

AlecK
Aug 27 2019 10:30

It's in 3000:2018; which has not yet been cited by ESRs.
   

SaintAlan
Aug 27 2019 11:22

Seems a bit OTT to require a lockable isolator if it needs to be beside the HWC.
The breaker in the switchboard is rated as an isolator so would the lockable plastic clip-ons be acceptable?
Or should we be looking at a local plug/socket for isolation like the gas regs specify?
   

AlecK
Aug 27 2019 17:00

Think of it from the plumber's viewpoint.
And in the certain knowledge that most switchboards are very poorly labelled.

What the new rule is doing is bringing water-heaters into line with other types of equipment that may need to be safely serviced by other (ie non-electrical) trades.

The switches / PCUs we have been used to using do not proved isolation. Never have. What we've been doing. for years now, is relying on an Exception that allows the means of isolation to be at swbd. The Exception is being removed, and at the same time a new rule is being added so that one switch will isolate all supplies to the HWS (some of them have several supplies).
   

Sam1234
Aug 27 2019 17:54

Do gas hobs require plug and socket by law? Is hard wiring them not aloud?
   

DougP
Aug 27 2019 21:09

You can hard wire a gas hob. But then you would have to fit a switch.

In 3000:2007 4.18 it says all live conductors, but that has been modified in schedule 2 of the ESRs to "all active conductors".

In 3000:2018, it will need to be a lockable isolating switch (all active conductors), unless the gas hob is plugged in.
   

AlecK
Aug 28 2019 09:20

That "change" is actually not a change at all, only a clarification.
In both editions, the switch is one of three acceptable "means of isolation". It follows that if a switch is a "means of isolation", it has to be an isolating switch; because other types of switch simply cannot provide isolation. All that's been done is draw users' attention to what should be obvious - in order to avoid misunderstanding by those who either work with their brain in neutral or try to find loopholes.