[chbot] Electrical Safety

[Robin Gilks]

> I almost hesitate to re-open this old chestnut.
>
> I'm considering the purchase of a generator or inverter in the 1-2kVA
> range and was wondering about electrical safety, especially with some
> inverter/charger/UPS combinations.
>
> I found some products from China on trademe without any obvious claim
> to meet AU/NZ electrical safety standards. When I checked back on the
> standards route I was surprised to discover that new imported items
> may be exempt by a "Conformity Co-operation Agreement" in Section 80
> Part 2(b) of this document:
> http://www.legislation.co.nz/regulation/public/2010/0036/latest/DLM2763717.html
>
> So referring on to the cooperation agreement I have little idea how to
> check whether a device I plan to purchase is really safe or not.
> http://www.med.govt.nz/energysafety/appliances-fittings/electrical-appliances-fittings/core-requirements/international-cooperation-recognition/current-mras/new-zealand-china-2013co-operation-agreement
>
> At the end of the day I want to live long and prosper safely through
> the odd power cut or DIY activity away from mains power. Any thoughts
> on that? Maybe running an inverter/charger or generator through an
> appropriately connected RCD is the prudent way to go.

A lot depends on what part of the system you are trying to make safe.

 * exploding batteries due to too high a load
 * smoking inverter due to poorly specced parts
 * grid-mains isolation (anti-islanding etc) to not kill your neighbour
 * output voltage being within the range of the appliance connected to it
 * output waveform being appropriate for the device being powered
 * earth isolation to prevent dangerous current loops
 * earth leakage breaker for personal protection and fault detection
 * insulation appropriate for the voltages present in the system


For example, I use an electric hedge trimmer running on a small 2-stroke
generator which has a floating mains output. If I cut the cable, the
chances of me being across both live and neutral is pretty slim compared
to livening the cutters if I hit the live on a grid-mains connected
trimmer.



-- 
Robin Gilks