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[Richard Chirgwin]

On 27/04/11 4:09 PM, Kim Holburn wrote:
> On 2011/Apr/27, at 2:59 PM, Richard Chirgwin wrote:
>
>> Indeed. What follows is a true story from the 1990s, although I can't
>> remember whether the company was Synoptics or someone else ...
>>
>> The occasion was a trade show at Darling Harbour, Interop or perhaps
>> ATUG (back when it had exhibitions as well as its conference). The
>> equipment to be demonstrated needed Ethernet cabling.
>>
>> The contractor ran the cable by wrapping it around a pipe up in the open
>> ceiling. Also running along the same pipe was one phase of the
>> three-phase power supply; the network switch was connected to a
>> different phase; and when the Ethernet port was plugged into the switch,
>> it smoked. So I do think there are *some* good reasons behind cabling rules.
>> OK, that's an extreme example. But we have just had a national scandal
>> because insulation installers got killed using a staple gun where
>> there's live cabling. Can I imagine someone trying to nail a saddle for
>> an Ethernet cable to a noggin, and nailing through a 240V cable they
>> hadn't noticed? Easily.
> I was going to comment on that.  Firstly those regulations are state and possibly even local council regulations so may differ in different states.
>
> Secondly it's amazing we have all this regulation and evidently it didn't apply during the insulation installation ... except it did - some states had decent regulations and had no issues.
>
> So if you live in Queensland you're probably allowed cable your own house.
>
>
>
>
The cabling regs are ACMA rules... that's odd, actually, sparkies are 
state-licensed, but Ethernet is ACMA.

But I know what you mean. The rules *did* apply during insulation 
installation, it's just that some people ignored the rules. Of course, 
if someone is a rat bastard and sends untrained kits around electricity 
with a staple gun, that must be the government's fault.

I just had a fault with a backup generator for a solar installation, so 
I called the person who installed the solar. The problem turned out to 
be the cowboy who delivered and installed the generator, not the solar: 
he cut cables from the old generator, stuck on some 15 amp extension 
cable plug / socket pairs, and that was it. Problem is, an empty battery 
can suck WAY more than 15 amps - I've seen peaks of 35 to 40 amps.

So: in summer, there's no problem. The batteries don't hit "dead empty", 
if there's a couple of bad days it's just a light run with the charger. 
In May, however, a couple of bad days cause a huge suck from the 
generator - which killed the socket, caused a short-circuit, and cut in 
the safeties on the generator. A good thing, too: without the safeties, 
there would have been a fire.

Ethernet cabling regs look silly if you ignore the environment they 
might live in. I know plenty of IT techies whom I would not trust 
anywhere near voltages more than 15V...

RC