[chbot] Electrical Safety

[Charles Manning]

I'm confused.

Buying a generator or an inverter? They're hardly the same thing and
need to be considered differently. It is like asking questions on how
you should I cook a duck or a fish.

The generator will, presumably, pump out AC and will need all of
Robin's worry list.

An inverter is, presumably, taking you from a battery bank/solar to AC
to attach to the mains and maybe pump some back into the grid. In that
case you need all Robin's worry list on the AC side as well as all the
issues on the DC side. DC is, sometimes, a less manageable beast.

Bottom line though is that you'd probably be best served getting in a pro.

On Wed, Aug 20, 2014 at 5:37 PM, Mark Beckett <m.beckett at amuri.net> wrote:
> My suggestion is RCD at the source, however you really need to have an earth
> to connect the generator to.
> In my case I've usually treated the load as a plug in device, and not
> bothered with trying to connect back to the switchboard, etc.
>
> What you might find is that the frequency is way off and the voltage
> fluctuates like crazy, so some care is required.
> Luckily most monitors (and I assume TV's) seem to simply rectify the mains,
> then do the magic with the DC voltage.
> So they should be fine.
>
>
> Mark
>
>
>
> Charles Manning wrote:
>>
>> To add to Robin's worry-list, you also need to consider the DC side
>> too... DC arcing is a pig as it is not suppressed by zero crossing.
>>
>> C'mon Richard... live on the edge. That you lived over 30 is just an
>> accident of time and place. If you'd been born more than 100 years ago
>> or in 3rd world, odds-on you'd never have graced us with your
>> presence.... which would have been a loss for us.
>>
>> On Wed, Aug 20, 2014 at 4:49 PM, Robin Gilks <robin at gilks.org> wrote:
>>
>>>>
>>>> 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
>>>
>>>
>>>
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>>
>>
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>
>
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