Water and electricity don't mix

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Joined:Sat Oct 15, 2011 11:31 am
Location:Melbourne, Australia
Water and electricity don't mix

Post by jonoxer » Thu Nov 10, 2011 10:49 am

I won't make it a habit of spamming the forum with link-bait for my personal blog posts, but it's kinda related to Arduino so just this once I'll give in to the temptation: http://walkti.me/375.

Joined:Tue Nov 01, 2011 10:14 am

Re: Water and electricity don't mix

Post by LukeW » Thu Nov 10, 2011 8:56 pm


You're not really having much good luck with your renovations, are you Jon?

Hopefully it all gets sorted out and finished off smoothly in the not-too-distant future.

Joined:Wed Nov 02, 2011 11:47 am

Re: Water and electricity don't mix

Post by sawtellda » Thu Nov 10, 2011 10:16 pm

Hope you dont suffer too much from all that water damage Jon.

Something that rang true when listening to your walktime blog was the "when space junk goes bad" situations that eventuate particularly in regard to lighting. We are all conditioned to be able to fumble at a wall and get some lights on any time there is power available.

Over many years experience I learnt to apply a few KISS principles to my commercial and residential designs which helped to keep the after hours callouts and phone requests to a minimum.

Inverting the logic of Form C control relay allows lights to be designed to fail ON and not OFF. Worst case you can always shut down lights from the circuit breaker, and you have suffient light to find that missing torch you'll need for the return journey from the switch board or to locate and fix any problems with automation.

My best solution however has been to use mains or low voltage impulse relays such as the ones in the link below. http://www.hevacomphelp.com/elec/1pdf/HAG/0033.PDF
Hager, Telemecanique, Finder, and Merlin-Gerin all manufacture some variations of these in M36 Din form factor.

The advantages are
- Require no holding current. This relay and any automation output only needs a short pulse to operate which helps with power consumption.

- These relays have a toggle actuator are mains rated and can be mounted direct within garden variety DIN breaker enclosures. You have control of all switched circuits regardless of the state of any controls, power supply or automation.

- I retrofit application these relays can minimise the amount of modification/extra cables required in mains wiring. They can can provide a good point of demarcation/isolation and will fall easily within the scope capability and comfort zone of competent electrical contractors.

Just a suggestion/solution That I've been using for several years now and one that I hope others may find useful. I've found this strategy to be the best of both worlds in Automated applications

I hope you can get everything dried out over the weekend Jon.

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