Why are my LED flood lights semi-illuminated when off?

[readiescards]

I've put a few of these cheap LED floodlights about:

http://www.ebay.co.uk/itm/-/192036357719

 

Apart from the fact they didn't like a super cheap non-sine wave inverter and kept blowing up so I've upgraded to a sine wave inverter and they seem fine.

 

To help the trades I've put some switched plugs on LED power cords:

http://www.ebay.co.uk/itm/261904475129

 

But when the switch is OFF the LED floods are partially illuminating - this is happening on all the LED floods I have with these switch plugs on.

 

Is it dangerous? A problem with the LED? A problem with the switch? A screwup by me?

 

Thanks for any tips

Paul

 

[Jeremy Harris]

It's almost certainly leakage current. 

 

If these are Chinese, then please disconnect them and take them apart to make sure that they have an earth connected - my experience is that very often they don't!  If the earth wire is properly connected internally, then check that the line and neutral are the right way around - again it's quite common for Chinese stuff to have them swapped, I've seen this on power supplies in particular, and once on a battery charger (not nice, it meant that the negative battery connection was sat at mains voltage................).

 

It's also possible that instead of a proper LED driver they may just be using a capacitive dropper, sort of OK if everything is properly insulated internally, but again Chinese stuff can be poor in this regard.

 

If you find that the light does have a proper LED driver inside, that the line and neutral are the right way around, and that the internal earth wire is properly connected to the alloy case, then you can still get leakage via the interference suppression capacitors fitted to the supply side of the switched mode LED driver unit.  The problem is generally current flowing via earth in this case, not enough to cause an RCD/RCBO to trip, but enough to make the LEDs glow.  If that's the case then the best fix is a double pole switch, but please disconnect the light and look inside for earth or wiring faults first. 

 

Sadly there are a lot of these that are just bloody dangerous.  I bought 4 very similar flood lights and all four had the earth wire loose and unconnected inside the case, and they were all sold by, and badged with the name of, a UK company.

 

[Crofter]

I have a similar issue with some gu10 lamps in my kitchen and it was suggested to me that it might be induced current, and that there wasn't anything to worry about. But it was probably Jeremy who suggested it so it'd be interesting to see why it's more likely in one installation that another.

[Jeremy Harris]

The main difference is that these LED flood lights are already earthed (or should be), as they have an alloy case. 

 

The GU10 LEDs are (supposed to be) double insulated, with no earth conductor connection, so induced current in the switched line can make them glow, with the return being via the non-switched neutral.  Fixing that problem is usually fairly easy, just make sure the earth conductor in the feed to the LEDs is connected to earth, even though it's not used as a protective earth at the LED end.  Doing this  stops the tiny induced current in the switched line (or rather, just gives it a lower impedance path via the earth conductor) and stops the slight glow.

Edited March 22, 2017 by JSHarris
typo

[Temp]

I believe this problem usually happen with indoor lighting because LIVE runs from the fitting down to the switch and back up to the fitting as SWITCHED LIVE. Therefore you have both sides of the switch in the same cable for some distance. Coupling between these two wires allows energy to bypass the switch. Typically this is enough energy to make LED glow dimly or for CFL to flicker on occasionally but it's not enough to light up a halogen or similar.

 

It's not so obvious how it's happening with your outdoor set up but you could try switching the neutral as well.

Edited March 22, 2017 by Temp

[Jeremy Harris]

Just to add that I found the post showing photos of the unconnected earth wire in similar Chinese LED flood lights:

With an earth conductor connection made to the case these lights are safe enough, and seem reliable.

[readiescards]

20 hours ago, JSHarris said:

t's also possible that instead of a proper LED driver they may just be using a capacitive dropper, sort of OK if everything is properly insulated internally, but again Chinese stuff can be poor in this regard.

 

Thanks Jeremy, attached a photo of the internals, I'm not sure if that is a proper LED driver or not?

 

The earth connection within the units look secure and ok to me.  However there is no earth connection in my setup as these lights are running directly from my battery inverter. Seems like I should add a connection to the world earth for safety reasons.  

 

I'm not sure if the live and earth are correct inside the unit, maybe someone can say from this photos (note these are from LED units that have failed but the working units are the same internally)

 

Though I still find it strange the lights are semi-illuminating and a double pole switch seems best solution - do these exist as 'in plug' versions like these units?

 

[Jeremy Harris]

The earth connection looks OK, and the COB LED in this unit seems to be direct drive, via parallel connected BP5132H high voltage constant current driver chips.  This arrangement means that the LEDs on the chip on board (COB) are connected in series and driven with full wave rectified mains.  A side effect of this is that, like some GU10 LEDs, it's possible to get a slight glow from induced current in the wiring.

 

What is puzzling is that the earth conductor in a three core cable should act to reduce induced current in the switched line to a very low level.  Clearly it's not doing this in your case, so it's worth checking that there is continuity from the earth conductor in the LED to the protective earth for the installation, as it's possible that the earth has been disconnected somewhere.

 

If all is OK, then the fix to stop them glowing is probably to fit a double pole switch.  Big Clive has some details about this type of LED flood light on his YouTube channel:

 

 

[Temp]

6 hours ago, readiescards said:

Though I still find it strange the lights are semi-illuminating and a double pole switch seems best solution - do these exist as 'in plug' versions like these units?

 

Not sure about that but you can get inline double pole switches like this..

https://boatlamps.co.uk/products/in-line-water-resistant-double-pole-switch

Just check the cable diameter will be ok. 

[Temp]

6 hours ago, JSHarris said:

What is puzzling is that the earth conductor in a three core cable should act to reduce induced current in the switched line to a very low level.  Clearly it's not doing this in your case, so it's worth checking that there is continuity from the earth conductor in the LED to the protective earth for the installation, as it's possible that the earth has been disconnected somewhere.

 

Good point.

[Jeremy Harris]

1 hour ago, Temp said:

 

Not sure about that but you can get inline double pole switches like this..

https://boatlamps.co.uk/products/in-line-water-resistant-double-pole-switch

Just check the cable diameter will be ok. 

 

Unfortunately that switch is only rated for up to 50 V, so not safe for use at 230 V AC.  The switches on  decent quality 13 A outlets are usually double pole, but worth noting that some of the cheaper types of 13 A outlet only have single pole switches. 

Edited March 23, 2017 by JSHarris
typo

[Steptoe]

On 22/03/2017 at 13:18, Temp said:

I believe this problem usually happen with indoor lighting because LIVE runs from the fitting down to the switch and back up to the fitting as SWITCHED LIVE. Therefore you have both sides of the switch in the same cable for some distance. Coupling between these two wires allows energy to bypass the switch. Typically this is enough energy to make LED glow dimly or for CFL to flicker on occasionally but it's not enough to light up a halogen or similar.

 

It's not so obvious how it's happening with your outdoor set up but you could try switching the neutral as well.

That's usually how it happens in a domestic, 

Can also normally be fixed by adding a snubber.

[PeterW]

9 hours ago, readiescards said:

However there is no earth connection in my setup as these lights are running directly from my battery inverter.

 

Wonder if the caps in the inverter are holding charge ..?? 

[Jeremy Harris]

There shouldn't be any capacitors on the AC side of the inverter, but with no protective earth (!) the earth conductor won't be doing anything useful.

 

With a DC to AC inverter (or generator) you must provide a protective earth with an earth rod or other connection to a known to be good protective earth conductor, to make the installation safe.  The installation should be wired in a similar way to a TT mains supply system, with a tested and known to be OK earth rod providing the protective earth at the supply end, in this case the inverter AC output side.

 

In theory a floating supply "could" be safe, as long as there is no possibility whatsoever of an incidental connection, or leakage path, that could mean that the inverter AC output terminals are referenced to local earth.  Frankly I would NEVER want to go near a non-earthed installation like this, though. I know people often completely ignore the instructions to provide a protective earth when running generators - that does not make it safe. 

 

 

(The above photo is a joke, before someone makes any comment about it........................)

 

Edited March 23, 2017 by JSHarris
typo

[readiescards]

I've ordered some double pole inline switches to hopefully stop the semi-illumination 

 

However the earthing issue raised, concerns me.

 

This is the inverter unit I am using:

http://www.ebay.co.uk/itm/LCD-DISPLAY-Pure-Sine-Wave-power-inverter-1500W-DC-12V-TO-AC-220V-230V-UK-Socket/131764980815

 

There is no earthing lug and no mention of earthing requirements in the manual.  So I'm a bit lost as what I should do to be safe for these metal LED lights (though no one should be touching them when they are on) and welcome any advice.

[Jeremy Harris]

The electrician that has installed/signed off your installation should have made sure that not only was there a proper earthing scheme fitted, but that it had been tested and was compliant with the regs.  AFAIK, being off-grid doesn't exempt anyone from the regs - if the system is above 50V AC then it is an LV installation and the regs apply as they would for a grid connected system.

 

For a generator or inverter powered 230 VAC system the requirements are that a local protective earth should be provided, in the same way as would be the case for a grid supply with no protective earth.  The 230 VAC connection from the inverter should be connected via a suitably rated fused double pole isolator to the consumer unit, with the protective earth being provided by a TT system.  This means fitting an earth rod, testing Ze to make sure it's within spec (no greater than 0.8 ohms normally) and using that as the protective earth for the installation.  The consumer unit, or other distribution point, must have a double pole RCD or RCBO.

 

The inverter you have looks to me as if it's a Chinese made unit, as it's marked 220V, yet it carries an EU CE mark, which is odd as the EU supply voltage standard is 230 VAC, not 220 VAC.    Fake CE marking is extremely common, so common that I suspect there are more fake marks around than genuine ones.  That doesn't mean the unit is inherently unsafe, although as it has a metal case and makes no mention of earthing one has to be just a bit suspicious.  The case should be earthed, but it would be wise to check that the output is really isolated from the case before doing this.  An electrician could test this in a few minutes, easily enough.

 

Finally, there is usually an insurance requirement that any temporary LV supply (and LV is anything over 50 VAC and under 1000 VAC) should be installed, tested and signed off by a competent person.  Even if an insurer doesn't require this, then it still important that it be done, particularly if a third party, like a contractor, is working on the house.  Failure to have a properly installed and tested LV electrical installation, even a portable site system, could make you personally liable in the event of an accident.

 

Edited to add:

Looking more closely at the photos of that inverter, I can't see any shutters on the outlet.  Well worth checking this, as a properly approved BS1363 outlet must have an earth-pin operated pair of shutters that close off the line and neutral sockets.  If it's as I think, without shutters, then the CE mark will definitely be fake and it would be advisable to do some testing to make sure that it has adequate internal insulation and isolation between both the DC input terminals and the output terminals, and between the output terminals and the case.

 

For use as a temporary, perhaps portable, supply then I'd suggest that the minimum requirement should be a decent earth rod and connecting conductor connected to the inverter earth, together with a plug-in RCD to provide protection to any user.

 

Edited again to add:

The seller gives a valid GB VAT number, but this traces to this flat:

 

Member State	GB
VAT Number	GB 243079218
Date when request received	2017/03/24 10:54:40
Name	JUNFENG CAO
Address	FLAT 93, ADDY HOUSE ROTHERHITHE NEW ROAD LONDON SE16 2PD

Edited March 24, 2017 by JSHarris
typo, plus an added observation on the outlet, and again for manufacturer details

[joe90]

And there,s me thinking that C.E. meant" Chinese Export " ?

[Jeremy Harris]

5 minutes ago, joe90 said:

And there,s me thinking that C.E. meant" Chinese Export " ?

 

I think it does for a lot of Chinese stuff, far more of it just ignores the safety regulations then most people realise.  Years ago I had a friend who had a business making custom bicycles and he imported almost all his components from either China or Taiwan.  He went to Shenzhen in China to meet some suppliers, and sent me some photos of his trip.  He spent half a day in one of the massive emporiums there, and one of the photos was of a stall that only sold stickers with things like fake CE marks, Windows and Apple logos, etc.  I remember him telling me that it was very difficult for a small business to get manufacturers in China to adhere to any sort of standards, as they always want to try and reduce the cost by cutting corners.  He gave up with getting components from China in the end, having experienced non-existent adherence to specifications, and now buys only from Taiwan, where it seem that manufacturers understand the need to stick to an agreed specification.

[readiescards]

21 hours ago, JSHarris said:

 

Looking more closely at the photos of that inverter, I can't see any shutters on the outlet.  Well worth checking this, as a properly approved BS1363 outlet must have an earth-pin operated pair of shutters that close off the line and neutral sockets.  If

 

Ah, indeed it has no shutters :-(

 

21 hours ago, JSHarris said:

Failure to have a properly installed and tested LV electrical installation, even a portable site system, could make you personally liable in the event of an accident.

 

Electrician coming Monday thanks for the heads up

 

[Jeremy Harris]

I'm really sorry to have had to be a bit negative but the risks of continuing to use an installation, or even portable, LV system with no earth and no real protection from electric shock are high.  Given that the inverter must have a fake CE approval (it cannot have passed with that outlet fitted, for a start) then I think it's very wise to get it tested. 

 

If it were me (accepting that I probably feel a bit more confident about taking stuff apart to examine it than some) then I'd open up the inverter case and examine the internal construction and layout, looking for visible signs that the design pays heed to the need for adequate isolation between the ELV DC input and the LV AC output, together with adequate insulation of high voltage areas from the metal case.  I'd also want to see that the earth pin on the socket was properly connected to the metal case.

 

Assuming all was OK internally, then using this as a temporary supply would then be OK, provided that a protective earth was provided, by means of an earth rod connected to the metal case and earth pin on the socket, together with a plug in RCD to provide protection downstream from the unit.

 

I really wish Trading Standards had the resources to stop all the non-compliant, and potentially dangerous, electrical stuff that is sold via Ebay and other on-line sellers.  Back when I was investigating and testing LED lights to use in our build I even found some lethal GU10 lights being sold by one of the very well-known DIY stores.  To their credit they did withdraw them from sale immediately when presented with the evidence (the LEDs used a capacitive dropper, so weren't isolated from the mains supply, and had bare chips on the front face, with a 50:50 chance that they would be at line potential..............).  In this case the seller is clearly in China, selling via a drop-shipping arrangement in the UK, and using a UK address as a mail box.  Trading Standards could do nothing more than close down his present seller ID, I think, and I'm certain the seller would just pop-up again within a day or two with a new ID.  My experience is that Trading Standard just don't bother chasing things like this, as they know they are wasting their time.

[ProDave]

Re LV and wiring regs.  I once wired a very remote public toilet. It had a 12V battery, a solar panel and small wind turbine to charge it, and it powered a small fan to ventilate a composting toilet, and a small 12V light.  Building control still insisted on an Electrical Installation Certificate.

[Jeremy Harris]

For an ELV installation like that then there's nothing in the regs that says an EIC is needed, so BC were out of order.  Common sense says there is still a fire risk, so over-current protection makes a lot of sense, but how on earth do you provide them with any meaningful test information for a 12V DC system?

[readiescards]

Ive order a Victron inverter as replacement for this Chinese one. The Victron coming with an earth and shutters on the socket.  So hopefully a safer solution all round

[ProDave]

1 hour ago, JSHarris said:

For an ELV installation like that then there's nothing in the regs that says an EIC is needed, so BC were out of order.  Common sense says there is still a fire risk, so over-current protection makes a lot of sense, but how on earth do you provide them with any meaningful test information for a 12V DC system?

You write a certificate with a lot on LIM or N/A and they accept it because all they want is a bit of paper that nobody ever reads or understands.

[Jeremy Harris]

9 hours ago, ProDave said:

You write a certificate with a lot on LIM or N/A and they accept it because all they want is a bit of paper that nobody ever reads or understands.

 

I guess this must have been for a local authority, I can't imagine anyone other than a council being so pedantic.