A new standard for dimmer 3 phase plugs

[p_c]

yep..... oops.


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Paul Collison

[David Ashton]

[quote="Jeff morgan"]I sent an email off to Standards about the Insulation /voltage rating of
the multi core cables we use etc. .

Also interesting thing, AS3000 /2007 now talks about third harmonics and adding them to final neutral calcs. Third harmonics and higher Should be taken as 100% and added onto the maximum out of balance load to determine neutral size.
This may have an impact on Plugs etc.

It is interesting that the people setting these standards would appear to be unaware of the `actual neutral currents in dimmer systems.If these people don't understand these basics it's hardly surprising your average sparky doesn't
Who are they?

[Danny]

Can you post a link to that spreadsheet??

Something that bugs me is when you hire powerlock leads from many companies the neutral cable is significantly smaller than the phase cables

[Andy Ciddor]

[David Ashton]

Any company which hires you neutral leads smaller than load leads is clearly not competent in the area and are creating a safety hazard, if the supply is for dimmers, it is dimmers that are the specific problem, with switch mode supplies following some way behind.

[rossgo]

sorry to bring up an older post but i found stuff on the issue of Neutral burnout

If anyone has AS3000 look under clause [b]3.5.2[/b] (pg126)
it says in section (b)(i) and (ii)

Multiphase circuit, The current-carrying capacity of the neutral conductor of a multiphase circuit shall not be less than that determined in accordance with the following

(i)Harmonic currents Where a consumers main, submain or final subcircuit supplies a substantial load that generates harmonic currents (eg fluoresent lighting, computers, soft starting starter, variable Speed devices or other electronic devices,) The third and an higher order harmonic current generated in the equipment shall be added to the maxium out of balance load to determine the current to be carried by the neutral conductor

it goes on to say

(ii) consumer mains, submains and final subcircuits, The current-carrying capacity of the neutral conductor of a multiphase consumers mains, submains or final subcircuit shall be not less than that of the current-carrying capacity of the largest associated active conductor,

and an exception says

3(b) a multiphase final subcircuit, may have a current-capacity less than that of the largest associated active conductor, provided that the predominant load consists of multiphase equipment and the maxiumum out of balance current, including any harmonic component.
is not less than the maximum out of balance current, including any harmonic


In my opinion these 3phase plugs that are attached to dimmers either 32,40,50 Amp clipsal 56 series ect are not designed to be used for devices with out of balanced harmonics like that of a heavily loaded dimmer rack.

will be interesting on what the manufactures like jands, ETC, theater light ect say about it
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ROSS CARDWELL
FREELANCE LIGHT & SOUND, SYSTEM TECH
SPARKY

[Andy Ciddor]

[Bivio]

So only newly installed dimmers and distro boards can benefit from oversized neutrals in practical terms? Unless you spend a lot of money on existing installs, running bigger neutrals to the sub station supply.

As has been previously stated we're chained to what's in venues and wired to our portable dimmers and distro boards, to fit in with what's already out there. If we limit burn outs at the plug end, through thicker neutrals, the typical three phase principals don’t allow for our unbalanced loads.

What would the manufacturers say? I'm sure their designers know the limitatations but have to work with what's available.

If a distro board for a building is near capacity and an electrician / HVAC installer puts in a 6kw split system for the office area, they think its fine to run it off the overly generous dimmer supply. Who am I to argue, they've got the authority and nothing's blown up and admittedly the alternative is very expensive.

They didn't take too long to introduce insulated pins on 240v plugs, when it was decided, but that impacted and affected more people and didn’t involve retro fitting.

[David Ashton]

The crucial factor in this is that the neutral pin on our stupid plugs has half the cross sectional area of the actives, the same size pin runs 20 amps max on the 20A/3 phase plugs and carries 50 amps on a 40amp 3 phase plug, it's pointless to use heavy neutral conductors and feed them into silly little neutral pins.Surely the geniuses who deem re-wireable piggy backs "dangerous" and turn our 10a single phase plugs into 15a by increasing the size of the earth pin ought to be able to figure out that the situation is serious, but when there is a major fire and lots of kids burn to death somebody might actually do something, and yes I'm pissed off with these stupid plugs and the stupid "authorities" who allow their continued use.

[Bivio]

[hdmcc]

Im not that flash with power knowledge (i know enough not to overload a circuit with amounts of equipment on them) but, last year working for a company we did an install in a church and we were installing 2 jands HP12 dimmers and after we fitted them to the racks and went to plug them in we discovered they had been fitted with a 40 amp plug (it had 2 sticky-out plastics bit instead of the usual one)

so we called our jands rep and asked why and apparently they got made to start fitting them because logically, 4 10amp circuits to one phase is 40amps not 32 or something like that.

so maybe things are already changing.

thats my 2cents atleast.

[David Ashton]

It is of course a pure "con",exactly the same plug, exactly the same undersize neutral pin, exactly the same danger, but more expensive, and the real, safe solution namely using 60A CEE plugs would be much cheaper as well as infinitely safer.

[Andy Ciddor]

[David Ashton]

As to cost I can buy from Europe a 63 A plug for $40 and the socket for $55 and I could probably halve that cost buying in China, seeing that you will be ripped off over $100 fot a Aussie plug alone, the cost of change argument does not stack up.

[Andy Ciddor]