Plastic led floodlight 20w has only live and neutral but no earth

[bernardgreen]

No, it is Class 2 and, as such, is better without an earth.

Why is it better without an Earth ? The only reason that it could be "better" is that it avoids the risk of electric shock from an exported Earth that is not a Ground potential.

That's why they made it Class 2.

It is also cheaper to produce a ( so called ) Class 2 device and self certify that is by virtue of it's design Class 2 ( that route avoids the need to actually test it is Class 2 )

A watt or two?? More like 15W heat dissipation at least

The driver shouldn't produce more heat than about 10% of the rated wattage of the unit.

 

[EFLImpudence]

Why is it better without an Earth ?

Earthing is not a good thing in its own right. It is a necessary evil in order to disconnect the supply in the event of a fault anywhere on the installation which makes live all the exposed metal parts of electrical items.
Removing the need to earth metal parts by double insulation and/or plastic construction is therefore considered better.
It would be better if nothing ever needed earthing.

The only reason that it could be "better" is that it avoids the risk of electric shock from an exported Earth that is not a Ground potential.

No, you are thinking that the actual earthing is a good thing and not the reason it is necessary.

It is also cheaper to produce a ( so called ) Class 2 device

Best of both worlds, then - although I can't see why there is any difference apart from more insulation.

and self certify that is by virtue of it's design Class 2 ( that route avoids the need to actually test it is Class 2 )

I don't understand the difference.


There really is no way round your thinking if you reject improvements because some may not be manufactured correctly.

Anyway, the OP's lamp would appear to have no exposed-conductive-parts to earth. You're not thinking the bracket, are you?

 

[EFLImpudence]

I think this arrangement makes the CPC requirement more easily envisaged -

 

[EFLImpudence]

So, perhaps, if the appliance comes with 2m. flex the distance may be unimportant.

 

[JohnW2]

Why is it better without an Earth ? The only reason that it could be "better" is that it avoids the risk of electric shock from an exported Earth that is not a Ground potential.

No. As EFLI has said, 'unnecessarily' creating any additional touchable earthed metal (whether or not related to an electrical installation) increases the chance of electric shock, by increasing the possibility that someone would be in contact with 'a second point of contact' (at earth potential) at the same time as they came in contact with something 'live'.

Kind Regards, John

 

[JohnW2]

I think this arrangement makes the CPC requirement more easily envisaged - ....

So, perhaps, if the appliance comes with 2m. flex the distance may be unimportant.

Indeed. If there is a plug fitted to the cable, then that removes any uncertainties as to what is, and what is not, 'fixed wiring'.

In the real situation we are discussing (with no plug on the cable), I still find it odd that, if the connection between CU and an item of Class II equipment consists of two bits of cable, joined at a JB (or equivalent), that whether or not the downstream bit of cable requires a CPC appears to depend on who connected that bit of cable to the item.

Kind Regards, John

 

[bernardgreen]

Outdoor floodlight with Live and Nuetral fed to it. Double insulated so perfectly safe.

Floodlight overheats and catches fire, not enough fault current to trip the over current protection device, Charged mass with Live and Neutral conductors in insulation that has burnt and been carbonised, carbon is conductve even if the plastic it came from was totally insulating the Live and Neutral before the fire.

Ingress of water is another way the exterior can become Live and again no tripping of a safety disconnect until some one touches the device while also in contact ( direct or indirect ) with Ground and takes enough current through their body to trip the RCD ( if an RCD has been fitted ).

And don't forget the "tingle" or "buzz" that some people feel on the exterior metal of some apploance and laptops which are supplied with ELV ( 19 volts for laptops ) from a double insulated no earth required power supply module. The ELV supply is floating around the mid point of Live and Neutral. ( 115 volts AC ). The ELV is capacitively pulled to the mid point and as such there current in the "tingle" is very small as long as the Power supply is in good condtion and is not damp.

 

[JohnW2]

Floodlight overheats and catches fire, not enough fault current to trip the over current protection device, Charged mass with Live and Neutral conductors in insulation that has burnt and been carbonised, carbon is conductve even if the plastic it came from was totally insulating the Live and Neutral before the fire.

Are you seriously suggesting that we should 'earth' plastic enclosures just in case they become 'carbonised' and hence conductive?

Kind Regards, John

 

[bernardgreen]

I am suggesting that a risk assesment of the various ways an item of electrical equipment can fail should be made and if necessary common sense applied to arrive at a solution.

 

[JohnW2]

I am suggesting that a risk assesment of the various ways an item of electrical equipment can fail should be made and if necessary common sense applied to arrive at a solution.

I can't disagree with that, but are you suggesting that application of 'common sense' could sometimes lead to the 'earthing' of a plastic enclosure?

Kind Regards, John

 

[EFLImpudence]

Outdoor floodlight with Live and Nuetral fed to it. Double insulated so perfectly safe.

Exactly. End of.

Floodlight overheats and catches fire,

Not likely to be touched until the power is switched off, then.

not enough fault current to trip the over current protection device,

There will be when the Line and Netral insulation melts.

Charged mass with Live and Neutral conductors in insulation that has burnt and been carbonised, carbon is conductve even if the plastic it came from was totally insulating the Live and Neutral before the fire.

Ok. So how do you ensure that the live conductor (or Neutral if there is an RCD) will connect to the CPC when it did not short to the neutral (or Line)?

Ingress of water is another way the exterior can become Live and again no tripping of a safety disconnect until some one touches the device while also in contact ( direct or indirect ) with Ground and takes enough current through their body to trip the RCD ( if an RCD has been fitted ).

Are you forgetting the exterior is plastic (or similar)?

Where exactly do you affix the unnecessary CPC to ensure it is in the live water track or area likely to be carbonized?
What about TTing it as well just to be on the safe side?


"Common sense" It seems it only works one way, doesn't it?
If, indeed, that is what is being used.

 

[stillp]

until some one touches the device while also in contact ( direct or indirect ) with Ground

Or an earthed CPC...

 

[ban-all-sheds]

I am suggesting that a risk assesment of the various ways an item of electrical equipment can fail should be made and if necessary common sense applied to arrive at a solution.

I suggest that before you suggest that you apply some common sense to the use of Class II items.

 

[bernardgreen]

I am suggesting that a risk assesment of the various ways an item of electrical equipment can fail should be made and if necessary common sense applied to arrive at a solution.

I suggest that before you suggest that you apply some common sense to the use of Class II items.

Too much trust is placed in "Class II" items which are Class II only for as long as they are not damaged.

 

[EFLImpudence]

Assuming you have a modern class 2 TV set, have you earthed it?
It's in a much more hazardous position than an exterior floodlight.

If so, where did you make the connection?