Best GFCI to avoid nuissance trips for bath fan?

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geoffspanky said:
GFCI's (Australia) are available in three types. AC, A and S. In practice if you have a standard AC type that is nuisance tripping you would replace it with an A type. The S type or selective GFCI's are for more demanding applications where voltage spikes and DC currents are present. Link Provided:http://www.nhp.com.au/files/editor_u...ools/dsrcd.pdf
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http://www.nhp.com.au/files/editor_upload/file/product-tools/dsrcd.pdf
We are discussing nuisance tripping from domestic / residential appliance loads, requiring 6mA RCD's or GFCI's to protect people, not industrial equipment tripping at 30+mA. The link shows 30mA GFCI breakers on din rails, not allowed in domestic dwellings.
 
Different countries have different codes, voltages, supply frequencies etc. Australian RCD's are 30mA or 10mA for medical and special purpose. They are designed to trip before the step touch voltage reaches a level that can kill people. There are other effective solutions as well such as low impedance earthing that is appropriate in some circumstances. Operating theaters for instance where nuisance tripping can risk lives.
I did suggest you speak to your suppliers. You pay for what you get.
You can argue codes but you can't argue science.



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geoffspanky said:
Different countries have different codes, voltages, supply frequencies etc. Australian RCD's are 30mA or 10mA for medical and special purpose. They are designed to trip before the step touch voltage reaches a level that can kill people. There are other effective solutions as well such as low impedance earthing that is appropriate in some circumstances. Operating theaters for instance where nuisance tripping can risk lives.
I did suggest you speak to your suppliers. You pay for what you get.
You can argue codes but you can't argue science.



Sent from my iPhone using Tapatalk
Click to expand...


Isn't it equal potential bonding rather then earthing?

And I agree, you can argue codes but cant argue science. Well said! :)

My money is still on a fault.
 
JHZR2 said:
How ow does that work? Is it effectively just a 220 ohm constant short from hot to neutral? Does it dissipate energy at all times?

i assume it was just wire nutted in at the fan junction box?
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I was going to suggest to place a resistive load parallel to the fan to absorb some of the kickback, may not be absolute perfect solution but may help.
 
geoffspanky said:
GFCI's (Australia) are available in three types. AC, A and S. In practice if you have a standard AC type that is nuisance tripping you would replace it with an A type. The S type or selective GFCI's are for more demanding applications where voltage spikes and DC currents are present.
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Thanks for the link.

The 300mA 80A DSRCD/S look ideal for a job I’m planning.

Now all I’ve got to do is find them.


PS
I’m with Mr Brooke, there’s a fault somewhere that a Fluke 77 won’t find.
 
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Perhaps there is a short somewhere that a fluke 77 won't find, but let's think probabilities...

old fan fan caused tripping...replaced fan and switch and wiring. New kit still causes tripping.

that would mean that there had to be a similar fault in the old wiring as the new wiring.

To me, that is improbable. Could one conductor set have damage that causes this? Sure. Would a replacement set have any practical probability of being damaged at installation?

To me it's improbable compared to the possibility of the GFCI being broken. And it's less hassle and possibly also less cost to replace the GFCI first...
 
geoffspanky said:
Different countries have different codes, voltages, supply frequencies etc. Australian RCD's are 30mA or 10mA for medical and special purpose.
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Roger that, thanks for the correction.

I knew Austrailia pioneared Single Wire Earth Return transmission lines, now used by the Los Angeles Dept. of Water & Power (DWP) for its 55kv distribution. The safety testing behind a 30mA RCD's may prove equally fascinating.
 
A German by the name of Georg Ohm would be better at explaining it than me. I must admit though I am not sure as to what percentile of people our countries code is designed to protect. I think I heard it is 95%. Obviously humans have different moisture content, conductivity, medical issues etc.


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mbrooke said:
Isn't it equal potential bonding rather then earthing?

And I agree, you can argue codes but cant argue science. Well said! :)

My money is still on a fault.
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Equipotential bonding is different to high integrity earthing which would be used in medical or IT installations.

Medical installations often use isolating transformers with an IT neutral.

<EDIT>
I’ve just read through that again
1st inst Information Technology
2nd inst Impedance Terra
 
Tony S said:
Equipotential bonding is different to high integrity earthing which would be used in medical or IT installations.

Medical installations often use isolating transformers with an IT neutral.

<EDIT>
I’ve just read through that again
1st inst Information Technology
2nd inst Impedance Terra
Click to expand...

Even in an ungrounded neutral medical power system an equal potential system is still needed. The first fault will not cause much current to flow but the second one will with voltage drop across the grounding conductors and in turn difference of potential which is reduced by equal potential bonding.
 
ptonsparky said:
As discussed, sometimes it doesn't matter if the fan is on the GFCI, they still trip.
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Well I didn't read all the posts and that a different question. But unless you are running one 20 amp circuit to the bathroom and not just to the receptacles, they shouldn't be sharing anything. Unless I missed that discussion too.
 
Old house, all k&t removed, 200A modern service, etc. But the fan was protected this way when we moved in, vendor instructions state GFCI, so why would I go against it, especially when I am seeing trips?
 
JHZR2 said:
Old house, all k&t removed, 200A modern service, etc. But the fan was protected this way when we moved in, vendor instructions state GFCI, so why would I go against it, especially when I am seeing trips?
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Just saying, it's not required to be on a GFCI, so why not take it off and avoid the trips. My guess would be that it's one of those little cheapy fans.
 
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