2.6.3.1 Exception 3 - Can you apply this to gas appliances?

[JamieP]

"This requirement need not apply to a socket-outlet or a connecting
device specifically for the connection of a fixed or stationary electric
cooking appliance, such as a range, oven or hotplate unit, provided
that"

Do we still consider a gas appliance as an electric cooking appliance due to it still needing an electric supply? Or is an electric cooking appliances one that uses electricity for it's heating?

My thoughts are that it doesn't apply to gas appliances but wanting opinions from others

[AlecK]

I wouldn't classify any appliance that uses gas as the source of cooking heat as an "electric cooking appliance".
They are gas cooking appliances.

This Exception was created because - historically - the MIMS elements of electric cooking appliances tended to absorb atmospheric moisture if unused for extended period; due to the insulating powder being hygroscopic, and the seals at the ends of the elements being less than perfect.
This is also why we still allow a lower IR value when testing such elements.
The extra leakage current from low IR within the element could contribute to nuisance tripping of RCDs.

Modern elements have much better seals; so the Exception is not really justified any more.
As witness, the 2018 edition - already in force in Oz - no longer has this Exception for Oz; they have RCD on all final subcircuits for residential.
There were fears expressed that requiring RCD for ranges, water heaters, etc would create a massive problem of nuisance tripping - but it simply has not happened.
Therefore I would expect that this Exception is likely to vanish for NZ as well in next (2025?) edition.
Note that NZ very nearly went down the "all final subcircuit" path for 2018 edition;
although with an alternative of using a 100 mA RCD where a dedicated circuit supplied an (existing) appliance with significant leakage.
(true a 100 mA RCD wouldn't trip below 50 mA leakage; however anyone in direct contact would be suffering in order of 230 mA shock current - and the max trip time is the same)

The 10 k-ohm minimum for IR testing of MIMS elements equates to 23 mA; around the lower end of the tripping range for typical 30 mA RCDs.
But when using the alternative leakage test; the max permitted leakage for a Class II appliance is 1 mA.
Bottom line: if the RCD trips, there's a problem with the appliance that needs to be rectified.

A gas appliance with electric ignition simply doesn't have any valid reason to not be on an RCD

[JamieP]

Thank you, this is exactly what I thought

If there's one thing I've learned from you (there's heaps actually haha) it's that the words matter, if they wanted it to apply to any cooking appliance, they would have just said cooking appliance, the fact that they used electric cooking appliance was what made me feel like it meant just that and wasn't intended for those that use gas for the cooking purpose

Appreciated

[AlecK]

The original reason for a provision isn't always obvious - but there usually is one.

And yes, the words do matter. Both the words that are used, and the words that could have been but weren't.

Something that should be taught as a subject for all electrical trainees (and other trainees for jobs that use Standards) is '"How to read a Standard".
It's a key skill.
There are now rules for how to write a Standard, details of which are constantly being refined
- all to the purpose of reducing opportunity for misunderstanding.
But the basics don't change.

I find it sad that we now have to define "should" & "shall"; when these are not technical trams but just plain English.