Question re: Portable Gensets & ELD safety switches

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Folks,

A question I've come across recently:

We have a portable genset (Honda 5kva) which we use around the property for
working on fences etc, where we need 240V.  We have one of those orange
4-outlet ELD safety switches, which I bought with the idea it would cut the
power if someone was stupid enough to cut the power cord.

However, it has been pointed out to me the ELD wont trip because the genset
isnt earthed.
Does this sound right?

If this is correct, is there any way to get an ELD to work on a portable
genset?

Should I simply keep the ELD outlet for the shed?

I already have ELD's fitted to all the buildings as it is, so it would
really be only handy for the 4 outlets...

Any info appreciated.

Cheers,

Rod.......Out  Back




Re: Question re: Portable Gensets & ELD safety switches



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Short answer:  yes.

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Yes.  It must have an earth connection.  Earth it.

These devices work on a core balance system.  Current in the active conductor
balances the return current in the neutral when there is no ground fault.  When
you make yourself part of the circuit, providing a connection to (hopefully)
ground, the current through you = the difference between current in the active
and neutral conductors.  If this is sufficient it will trip the protection. ( If
it is below the trip threshold, in principle it is below the harm threshold
too.)

So the question is whether you present a circuit that will unbalance the core.
You will if you grab the phase (active) and the machine frame.  You won't if you
grab the phase and sit there isolated from the rest of the system like a bird on
a wire.  The good news is that as long as your contact with the set's output is
downstream of the sensing core, any situation in which you will get a zap will
cause an imbalance.

Leaving the set floating provides one form of protection, although not one I
would rely on in all circumstances.

And an earth leakage system won't save you from frying if you happen to connect
yourself between phase and neutral.

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I've seen contractors bang in an earth stake on the gensets on no-mains building
sites.  I've also seen lots that don't.

Re: Question re: Portable Gensets & ELD safety switches


Use mains supply and piss off the genny its a safety hazard

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for
the
genset
conductor
When
(hopefully)
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active
protection. ( If
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threshold
core.
if you
bird on
output is
will
I
connect
building



Re: Question re: Portable Gensets & ELD safety switches



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please explain how to do that when the nearest power outlet is 3k away ?

Re: Question re: Portable Gensets & ELD safety switches



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You can see why he's a fruitloop ...

Re: Question re: Portable Gensets & ELD safety switches



wrote:
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Its simple really , wire or maybe green generated electricity

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Re: Question re: Portable Gensets & ELD safety switches


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Dear village idiot,

Actually, it's not very simple at all.  Mind telling me how this would work
in the real world? Dont tell me; you're a 'green' contract fencer!  I can
see that your fencing rig would be a 40ft semi-trailer, so you can fit the
30-odd feet of 'green' renewable energy equipment...and the 50km of power
cord. What a smart little cookie you are!

Tell me, in what way would a renewable energy power source be so much safer?
I doubt your average vehicle mounted inverter will be earthed to ground
either.  As best I can see, the same issue applies.

Wotta wanker...

Cheers,

Rod.......Out  Back




Re: Question re: Portable Gensets & ELD safety switches



"Rod Out Back"

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**  Seems that you still cannot comprehend that if the AC supply is NOT
ground referenced then electric shock hazard becomes close to zero.

It is  *BECAUSE*  the regular AC supply  *IS* ground referenced that ELCBs
are needed to protect human life.

Folk working on construction sites in the UL and Europe have long used
portable isolation transformers to create an "earth free environment "  -
way safer than the usual one.



........  Phil





Re: Question re: Portable Gensets & ELD safety switches



"Phil Allison"

** Typo alert:


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..........  Phil



Re: Question re: Portable Gensets & ELD safety switches



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NZ too (historically), and I thin'k I've seen used ones in AUS.
ELCBs are cheaper and way more portable than a 20KG transformer.

Bye.
   Jasen

Re: Question re: Portable Gensets & ELD safety switches


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for
the
genset
You want a proper residual current device so that anything not coming back
tot he gen trips the breaker.

Cheers.

Ken



Re: Question re: Portable Gensets & ELD safety switches



"Rod Out Back"

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** If an ELCB does not trip because the generator frame is not earthed -
then a person in contact with either AC wire is not getting a shock.

If a person manages to be contact with both AC wires -  they will get a
shock, but an ELCB will not help them anyhow.



..........  Phil






Re: Question re: Portable Gensets & ELD safety switches



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FFS, just use modern DI tools and all ya will need to worry about is
lightening and the tax man!

--
Regards ......... Rheilly Phoull



Re: Question re: Portable Gensets & ELD safety switches



"Rheilly Phoull"

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**  That is a VERY dangerous myth.

Are not the business ends of electric drills and saws etc made from metal ?

Can you not touch them ?

What if they become live through contact with a cable ?




........  Phil





Re: Question re: Portable Gensets & ELD safety switches



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Why do you think it is mandatory to have RCDs fitted to all outlets on
building sites? Perhaps tradesman all use ancient power tools? Reasoning
like yours is beyond stupid.



Re: Question re: Portable Gensets & ELD safety switches


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Reminds me of the time I was helping a Telecom Liney splice a massive
co-ax cable, I had my back turned to him and heard the alternator bog
down and almost die. As I turned around I saw him flopping about the
cable pit and then the alternator stalled.

     He'd dropped the hot air gun into knee deep salt water at the
bottom of the cable pit and nearly fried himself as there was enough of
an earth return to the gen set frame sitting on the wet salt pan surface
to pass a current via the DOUBLE INSULATED hot air gun.



Re: Question re: Portable Gensets & ELD safety switches



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In this situation, provided there is enough current flowing through
the earth lead (from the description i am guessing there is) then an
ELCB would trip.

As Phil said, without any return, an ELCB is useless. For double
insulated tools, unless you are working in a situation where there is
a possible ground path to the genny, then you will not get a shock
unless you touch the active and neutral, in which case an ELCB will
not help.

For tools that are not double insulated, then an ELCB may be useful.
That is if there is any possible way for one to be in contact with a
active peice of the tool and an earthed peice of the tool.

My advice, keep the ELCB, it cant hurt.

Re: Question re: Portable Gensets & ELD safety switches


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yeah if the generator output is earthed a RCD is a good idea.

Bye.
   Jasen

Re: Question re: Portable Gensets & ELD safety switches



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You have been mislead. If the genset had no path to earth then you would
never get zapped unless you:

1. ... came into direct contact with the genset.
2. ... were the link between active and neutral.

Obvioulsy an RCD will work on a genset so make sure you use it.
BTW an RCD is useless in scenario no 2 above.



Re: Question re: Portable Gensets & ELD safety switches



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 Hi Rod,
This issue is covered very extensively by Mines Department requirements for
the use of generators on mine sites. The Mines Department electrical
inspector for your area can provide you with literature that details how the
generator and protection system, including the earth, should be wired for
best protection.



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