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Posted By Topic: Install an instant electric hot water in shower?

Mar 11 2019 20:31

Is it prohibited to install an instant electric hot water shower unit IN the shower?

I have seen them installed overseas (normally mounted next to the shower head) but looking at the standards "Installation of electrical equipment in Zone 0 must be IPX7 and no switches or socket outlets installed." I will need to hardwired the unit?

Can someone please confirm am I reading the standards right?

URL Link similar unit but not the exact brand/model

Mar 11 2019 22:02

Because it's not zone 0, it's zone 1. Zone 0 is below the waterline.

Zone 1 only requires IPX4


Apr 17 2019 09:11

These are installed inside shower enclosures in Germany and France, but don't seem common in NZ.
I took the cover off one (as sparkys do) and was not impressed; the sealing was not really 'waterproof' and the exposed push-on terminals inside were green and corroded.
I would not install one inside a shower even if the regs allow it.


Apr 18 2019 12:47

They’re not that common in NZ. I think maximum demand limits their use especially in domestic situations.

I’ve installed a few units. One was in a small bedroom above a commercial business.

From memory I think I ran a dedicated 6 or 10 mm2 2 c + E TPS from the MSB on a c32a RCBO. Some of them have big elements.

They do look off putting (why would you install something like this in a shower unit) but they are safe as long as it’s installed as per instructions.

Oct 16 2019 10:52

Following a discussion about in-shower water heaters in another forum, the current wiring rules treat these the same as HW cylinders and do not require RCDs.
I think it is ridiculous to install any electrical equipment inside Zone 1 wet area without an RCD, however some argue the minimum standard is acceptable even if the overseas manufacturer's instructions specify them.
Any thoughts or links to other standards to clarify this?

Oct 16 2019 11:15

2.6 does not require RCD for a subcircuit supplying a (directly connected) water heater. requires precautions as per table 6.1, and for Zone 1 that means IPX4, with no RCD mandated.

Under 2018 edition, MIs become mandatory. Until that's cited, ignoring MIs is simply poor practice.

IEC 60364-7-701 calls for RCD on "all circuits" to areas containing a bath or shower; so I would not be surprised to find AS/NZS following this in future.
Noting that Oz have already moved to require RCD on "all final subcircuits" for domestic.

Oct 16 2019 11:46

The point in that other forum topic was, that another electrician came along to repair the water heater and told the client that it was illegal because it didn't have an isolating switch and wasn't supplied through an RCD.

As you know, that electrician was wrong. There was nothing illegal about the installation.

Anyone can do more than the minimum requirements if they want to. It's probably best to let your customer know that's what you're doing though, and why they are paying more. Otherwise another electrician might come along later and tell them that the extra work they had to pay for was unnecessary.

Communication with customers about the work is important. Also important is not telling customers that the work someone else has done is illegal, unless you're 110% sure.

Oct 16 2019 18:13

My concern with being required to follow MIs is mostly that a lot of them are very clearly not written for here, or quite onerous to comply with.

Yes, regs say they have to be compliant...

For example, most Daikin commercial equipment says to supply it with a 15A fuse, and almost everything including 50kW input chillers requires an 'earth leakage circuit breaker' or 'breaker with a current leakage protector'.

Oct 17 2019 08:20

In most States of Oz, MIs are already mandated, due to the way they apply "3000" as: "must comply with Part 1, Part 2 is deemed to comply with Part 1".
It doesn't seem to be causing a lot of problems.