So please give details and not a vague/flippant reply again.The same hazards as earthing any other part which does not have to be earthed.
So please give details and not a vague/flippant reply again.The same hazards as earthing any other part which does not have to be earthed.
And I'm also aware of some of the regulations which you are trying to inform this community are dangerous...It was neither flippant nor vague.
I am sure you know why earthing isolated parts is hazardous.
That is a good point, I was thinking about faults where live parts come into contact with "exposed conductive parts".Indeed.
Are you suggesting that a failure of the insulation which allows ones to touch both sides of a a floating supply (e.g. both terminals of a lampholder) constitutes more than a single fault?
Yes.Quite so - and, as I have said, I think a problem could only arise if one of the multiple faults had the effect of rendering the supply no longer floating.
The two tend to go hand in hand though. If you bond the frame/case of the isolating transformer to earth (to protect against faults on the primary side) and you bond the frame/case of your isolating transformer to the exposed conductive parts on the secondary side (to protect against multiple faults on the secondary side) then you have indirectly connected the exposed conductive parts on the secondary side to earth.Indeed, but we're not talking about bonding different bits of metalwork to one another but, rather, of bonding the exposed-c-p of one (Class I) item to earth.
I don't know what you have been reading, but I have said no such thing.And I'm also aware of some of the regulations which you are trying to inform this community are dangerous...
So please once and for all give us details of these dangerous practices and regulations.
Quite so - but, as you imply in a subsequent post, that's merely a special case of the much more general truth that to 'unnecessarily connect to earth' any metal object in a building (and that includes door knobs, window frames and even spoons) which has an earth-referenced electrical installation will inevitably 'introduce potential hazards'.If one had a 240V battery (or generator I suppose) running a single appliance then surely connecting the appliance metal case to the house supply earth would only introduce hazards to the appliance and user?
If one had a 240V battery (or generator I suppose) running a single appliance then surely connecting the appliance metal case to the house supply earth would only introduce hazards to the appliance and user?
Your answer to a straight question:What hazards?
I call that vague as you have not made any attempt to put any information forward and flippant as you have not treated it in a respectful manner.The same hazards as earthing any other part which does not have to be earthed.
So please give details and not a vague/flippant reply again.
I call this even more vague and certainly avoiding providing any requested information.It was neither flippant nor vague.
I am sure you know why earthing isolated parts is hazardous.
Do you mean you bonded the heater or the generator?The reason I'm pursuing this is simple, I have quite frequently assisted with installing temporary generators to provide additional power in a building (sometimes for a single appliance like heating or chilling) and there is no way on this earth we'd have ever got away without bonding to the building earth. And now here you are telling me I know it's hazardous, contrary to the opinion of the IET.
However you converted it into powering a device from a battery or generator. OK it may have been me who moved the device indoors but I don't see that makes a difference.The thread is about a string of lights supplied by an isolating transformer.
And now you are moving on another tangent by suggesting earthing a device which is not designed or intended to be earthed.Substitute an electric shaver if you want - connect the shaver to the house earth or not?
So, are you saying you would earth a device supplied by a battery?However you converted it into powering a device from a battery or generator. OK it may have been me who moved the device indoors but I don't see that makes a difference.
Well, surely you must know - will become live in the event of a fault on the house supply, will provide a path to earth of negligible impedance if a person simultaneously touches a house live conductor, once earthed might require bonding etc - all the reasons for not earthing a spoon.And you still haven't explained the hazards you say will be introduced if the metal skin is connected to earth.
Not really.And now you are moving on another tangent by suggesting earthing a device which is not designed or intended to be earthed.
I suspect that you may need to think more widely than that, and that that that "another natter" is probably more important than you imply.That is a good point, I was thinking about faults where live parts come into contact with "exposed conductive parts". .... Faults that directly expose conductive parts to touch are another matter.
As you say, it's down to swings and roundabouts (aka 'a risk assessment'). However, as I've said, if one is going to connect (by whatever process, directly or indirectly, and whatever one calls it) a point on the secondary of an isolation transformer to earth, then one will have negated most of the reasons for having an isolation transformer (for isolation) - so probably might as well do without it (for isolation)?So if you don't bond the CPC of the appliance to the transformer frame/case you create a risk if there is a fault in the transformer and simultaneously a fault in the appliance. If you do bond the CPC of the appliance to the transformer you bring the risks associated with unnecessary earthing.
Just to remind the major part of this thread is all about adding a classI product to a floating supply. My comments are based around that scenario, not classII products.If you think items supplied by isolating transformers should be earthed then it must apply to a shaver.
So, are you saying you would earth a device supplied by a battery?
You have said that you have earthed - you said bonded - a device supplied by a generator but haven't answered my questions as to any specific reasons why?
Well, surely you must know - will become live in the event of a fault on the house supply, will provide a path to earth of negligible impedance if a person simultaneously touches a house live conductor, once earthed might require bonding etc - all the reasons for not earthing a spoon.
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