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Posted By Topic: Gas Range Isolation

Feb 04 2020 11:50

Had a topic on a Facebook group the other day that got me thinking

Do you think a switched socket outlet behind the range meets the definition of accessable when installed and adjacent as stated in 4.18.1?

I initially thought this was ok because I was focused on the accessable part and believed that behind the range was an accessable location but once I realized it also said adjacent it made me think twice and reconsider, just curious what other peoples views are

Note: this is a gas/electric freestanding, the open cooking surface is gas heating and the oven section electric

Feb 04 2020 12:47

So; no electric heating of the 'open cooking surface" so 4.7.1 doesn't apply.

For the gas aspects; 4.18.1 requires "means of isolation"; and offers 3 options.
Whichever option is chosen; it must be "adjacent" and "accessible with appliance in the installed position.
Accessible doesn't have a definition in 2007 edition, but it does in 2018. Accessible is less onerous than "readily accessible", but the words "in the installed position" give a clear indication that if you have to move the appliance, it isn't accessible enough.

So IMO it can't be behind the appliance (unless maybe the appliance has legs and a access space between them).

I would not be surprised of all the references to "accessible" in 4.18.1 become "readily accessible" in next edition. The current wording came directly from the gas installation Standard (5601.1).

It's been tweaked for NZ so that only all active conductors need to be switched. Also to clarify that if a switch is to be the "means of isolation"; then it really has to be an isolating switch [2018 edition]. The rest is as it came; and now that there's a definition of "accessible'; it would be natural to review all clauses that use either term and choose which is more appropriate in each case.


Feb 04 2020 15:43

I was using the definition of adjacent from the 2018 edition as a guide

The wording for accessable with the appliance installed is a little confusing because behind it to me still meets the definition of accessable when it's installed but I think I agree they probably used that wording to mean that it's needs to be able to be accessed without moving the appliance so that it's supply is isolated before any movement occurs

Just wanted some opinions, I'll stay away from putting them behind unless using 4.18.1 b and having a separate switch or the usual socket outlet in a cupboard near etc

Do you believe being in a cupboard to the side of the unit for either a socket outlet via 4.18.1 a or a switch that controls a socket outlet via 4.18.1 b meets the definition of adjacent in the 2018? I understand this doesn't apply to us yet but just curious

Feb 04 2020 16:49

you're right, it is less clear than it should be. that's because most of the places "accessible' has been used, the word was there before we had a special definition. so historically the meaning has been 'can be got to; but maybe needing more effort that 'readily accessible'; so may have to open / undo / unlock something."

And this one, as i said, was originally drafted by a gas committee and not by an electrical committee. My view is they shouldn't have been writing an electrical rule in the first place. But while we can't be absolutely certain as to what they intended; we can apply logic, and ask ourselves why those words about appliance position were used. Since no committee just throws words together, we can surmise their intent from the words used. Or sometimes from the fact that certain words were not used.


Does in a cupboard count as "adjacent"?
No; because in a cupboard is not "without obstruction" - you have to open the door of the cupboard.

While we're on 'adjacent'; there are some who believe that "the word 'adjoining' in the definition allows it to be "on" rather than "next to". The fact that some 4.19 says "adjacent to but not on" lends some support to this; though it certainly wasn't the intent. and again, 4.19 was written before we had a definition of 'adjacent'.


Feb 06 2020 22:45

What solutions are people providing for a pleasing looking isolation switch which is adjacent?? I'm sure on the block NZ they don't have a 56 series stuck on the wall. Or are we all breaking the rules and just installing functional switches?

Stupid gas rule written by gas guys, for does that work.

Feb 07 2020 08:35

Because as you said there are not really any appropriate isolation switches to that look nice enough for domestic most people opt for option (a) or (b) of 4.18.1

"(a) a plug to a switched socket-outlet; or
(b) a plug to a socket-outlet that may be located in an inaccessible
position but has a separate switch operating in all live (active and
neutral) conductors located in an accessible position;"

Note: ESRs have changed the requirement from all live conductors to all active conductors so the N need not be switched

By using a socket outlet instead of being hardwired a functional switch is sufficient, just need to ensure whatever option you choose as 4.18.1 says it's "adjacent to the appliance location and is
accessible with the appliance in the installed position."

Feb 07 2020 16:33

Option B is what I have provided. 413 in the cavity switched by a functional adjacent switch. The only benefit is that the unit is considered pretty much an plug in appliance now from an electrical pov, and there is no way any will be extracting the plug unless they pull the unit out as it is an inbuilt. I guess the rule is inline with the reason for plug in sockets for cookers and insulators for water cylinders, so other trades can perform works without illegally doing pew.