Imported: Stainless kitchen bench

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DougP
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Imported: Stainless kitchen bench

Post by DougP »

Tommy
Oct 17 2018 17:52


Hi I know a kitchen sink with plastic plumbing pipes doesn’t have to be bonded what if the whole kitchen bench is stainless steel there are a couple of power points above bench and a hob in the bench
Thanks for replies


DougP
Oct 17 2018 21:18


If the power points are mounted in a stainless splashback, then it may be necessary to earth it as a conductive building material - 5.4.6.1

But there is no requirement to bond a conductive bench top unless there is a continuously conductive path back to the ground, like a conductive water or waste pipe. Section 5.6

medistat
Oct 18 2018 08:52


But it would be good practice to bond it - they all have a bonding tag welded into the edge anyway. What does a metre of green wire cost anyway?

AlecK
Oct 18 2018 09:59


To answer the question; 4 mm2 G/Y conduit wire costs $1.52 /m + GST; Sell price say $2 +GST. There\'ll be several meters needed, and some time ($70 / h + GST). And a terminal or fastening. So total cost to customer somewhere around $50 + GST.

Good practice isn\'t doing things because you can, nor because it \"doesn\'t cost much\".
Good practice is doing something because it\'s worth doing; eg for better / safer electrical performance, or for ease of future maintenance.

I can easily leave a spare couple of metres of cable at any point, and \"it doesn\'t cost much\"; but is it serving any useful purpose?

I can decorate the switchboard with stick-on flower pictures, but that\'s not what I\'m being paid to do.

Or I could put an ashtray on a motorbike.

If there is a path to mass of earth (meaning that bonding is required and will serve a useful safety function); the place to do the bonding is not at the benchtop but as close to the mass of earth as practicable.

Or if, as DougP suggested, the metal is not double-insulated from an electrical circuit, then again there\'s a reason for it. But in that case it\'s earthing, not bonding; and the conductor used may need to be bigger depending on the size of the largest active conductor involved.

Apart from these cases, there\'s simply no sound reason to earth or bond a benchtop. Which makes doing it a waste of time and materials - and of our customer\'s money.



dlink
Oct 18 2018 20:08


money probably better spent installing RCD\'s on the socket circuits, based on a situation seen recently in a commercial kitchen with full stainless bench.

Tommy
Nov 11 2018 14:09


There are copper pipes connecting to the kitchen bench I was originally told they were getting replaced with plastic can no longer get earth cable to kitchen bench but both the pipes are bonded just before the kitchen
Is this ok

AlecK
Nov 15 2018 12:14


From description; yes OK.

We ONLY need to bond things that are in electrical contact with actual ground; NOT just because they are metallic.
So if the metal (cold) water pipe is in contact with ground (ie part if it is buried) it must be bonded, which should be done as close as practicable to where it exits the earth.
Anything (eg water heater, hot pipe, vent pipe roof, sink bench, etc) that the bonded metal pipe connects to after that is automatically bonded; nothing further to do.
The words of 5.6, and Figs 5.4 & 5.5, make this perfectly clear.
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