Is this legal?

[chrisatgt]

Hello all,

By way of introduction, I am Chris and I work in the repairs department of a company within the hydroponics industry.

We are concerned that we have a type of electronically controlled on / off timer that when it switches off, only the Neutral is disconnected. The Live is not switched leaving a permanent Live Feed into the contolled appliance. This is not a fault where perhaps double pole switching has failed or an error in the wiring of the device. They have been produced this way. We buy these from a supplier, the origin of manufacture we do not, as yet, know.

I think we all agree that this is bad practice and potentially unsafe but, is it against any regulation?

Thanks.

 

[Fin170]

If it's just switching neutral then I seriously doubt it's approved for sale in this country

 

[Des 56]

Product standards may permit this use,there could be a valid reason,Ask the manufacturer

Bs 7671 asks for single pole fusing of the live,as long as that is the case,I don't think Bs 7671 applies to the product,those standards may permit it as part of the its design purpose

This is only an opinion and may be a load of

 

[Octopus]

Hello all,

By way of introduction, I am Chris and I work in the repairs department of a company within the hydroponics industry.

We are concerned that we have a type of electronically controlled on / off timer that when it switches off, only the Neutral is disconnected. The Live is not switched leaving a permanent Live Feed into the contolled appliance. This is not a fault where perhaps double pole switching has failed or an error in the wiring of the device. They have been produced this way. We buy these from a supplier, the origin of manufacture we do not, as yet, know.

I think we all agree that this is bad practice and potentially unsafe but, is it against any regulation?

Thanks.

Are you sure its wired with the correct polarity? I'd be very surprised if the OEM wanted neutral switching only.

 

[monkeyelectric]

I had to replace a cord the other day on some dog clippers and they had a switched neutral too, i thought it odd but beings as its all enclosed i couldn't see an immediate danger and there is obviously a reason for them doing it this way

 

[ian.settle1]

I had to replace a cord the other day on some dog clippers and they had a switched neutral too, i thought it odd but beings as its all enclosed i couldn't see an immediate danger and there is obviously a reason for them doing it this way

And what happens should a fault occur when it is switched off with all the parts inside still live because the only the neutral has been switched off?

Very poor and dangerous practice in my opinion.

 

[ackbarthestar]

There appears to be several class II appliances that can be switched in either live conductor - usually some European applainces.

My first question would be whether the appliance needed a permenant live conductor connected when the electronic control/timer/sensor was de-activated.
and secondly,
I would have though Isolation would be achieved by pulling the plug....

 

[telectrix]

OP is working in hydroponics, so we should at least ask for some pot in exchange for advice.

 

[wade88]

I'll swap you 3 400w high pressure sodium lamps and some black out screening for a few bags and seeding buds

 

[ackbarthestar]

Lol, beaten to it .......
I suppose that fits the OPs header ........ replacement service fuses anyone ?

 

[Engineer54]

There appears to be several class II appliances that can be switched in either live conductor - usually some European applainces.

My first question would be whether the appliance needed a permenant live conductor connected when the electronic control/timer/sensor was de-activated.
and secondly,
I would have though Isolation would be achieved by pulling the plug....

I've found a lot of German made appliances that switch the neutral rather than the live. This may be because the DIN sockets/plug tops aren't polarised and protective devices are DP!! Then again i've come across French appliances that have been connected the same, and they do use polarised outlets!! lol!!

 

[Darkwood]

Without further info to the make and wiring plan of the controls we can't help... take boilers for example they can have fuses o both live and Neutral within the control panel ... this is out of the scope of the 17th in this case and actually is safer than just fusing the live, if its a control panel or board you are refering to then the help on here maybe misguided but having said that your concerns could be correct and il re-iterate we lack info to give a educated answer....

 

[Mainman]

And what happens should a fault occur when it is switched off with all the parts inside still live because the only the neutral has been switched off?

Very poor and dangerous practice in my opinion.

Well doggone?? I agree, it does sound dangerous

 

[AndyOz]

Switching the neutral is very common on German equipment. I spent time working on the maintenance of German trains in the UK. All differing ways of control depending on which system you are working on (braking, drive, doors etc....) It made fault findind very interesting and forced you never to assume anything.

So the simple answer to the questiom is "yes it is legal". Not good practice but legal.

 

[monkeyelectric]

And what happens should a fault occur when it is switched off with all the parts inside still live because the only the neutral has been switched off?

Very poor and dangerous practice in my opinion.

Well i will write to the manufacturer immediately and tell them all the thousands of clippers they have sold need recalling, like i said there's obviously a reason they done it this way, i can't think of any but its not like it can't be simply isolated from live by flicking a switch or pulling the plug, i couldn't see any immediate danger if a fault did occur as its class 2 and completely encased in plastic so if the only way to gain access to permenantly live parts would be if the plastic suddenly for no reason became conductive or you smashed the thing to pieces and then it wouldn't matter which was switched as it would all be exposed anyway!

 

[Darkwood]

As i said before this is all out of the scope of the 17th so opinions shouldn't be applied reletive to what we understand about BS7671.... you would be recalling half the countries electronic goods if this was the case... if it has a plug on it then it will be unplugged before stripping it down for possible repairs... consider a drill that has a broken neutral within the flex ... it will have a live side power throughout when trigger pulled this does not make it unsafe, same as control panels, circuit boards etc with N-switching/fusing ......if you are working on them you should be trained to do so which you are not with the title of Electrician given this its not going to be beyond your competence to make safe and see if you can possible repair a broken wire, loose connection etc....

All these parts you refer to with such N switching or fusing are usually powered via a DP isolation point if not on a removavble plug if you are entering a device and worried that the N has fused or switched leaving a live circuit throughout then you have not followed correct isolation procedures.

 

[chrisatgt]

Hello All,

Thanks for the replies and the interest. My concern was for our customers rather than for myself. The earth line in the supply lead is connected through to the output socket but not terminated within the timer. It is quite feasible to connect a device onto the output of the timer rendering its lead and internals live when the timer switches off. Depending on how well the customer's installation is protected will depend on how safe things are, something we have no control over whilst this "still live when off" unit is being used.