Reverse Polarity

[housewife59]

Apologies for intruding on your website - I am NOT an electician!! I would like some advice - a couple of weeks ago a MeterPlus employee came to fit a new meter in my house - he spotted a fault - said it was reverse polarity - the whole house was affected & told me to get an electrician to sort the problem. To cut a long story sort the problem was identified yesterday as aNEDL problem arising from underground cabling in the village 5 years ago. Basically I was told that the tails to the box on the outside of my house had been wrongly connected causing the reverse polarity. I would like to know what if any risks this has posed to me & my family over the last 5 years but more worryingly if the instalation was wrong to my property what about the rest of the village? Any comments or observations would be most welcome

 

[Golden_Boy]

sky box is polarity sensitive

Oh yes ?? Why is that then? The Power supply is a switch mode PSu derived from full wave rectification of an AC supply providing 350 volts DC for a switch mode PSU running at 50khz or so.... HOW can that make it " polarity" dependant?

 

[pushrod]

There are no "grounded" connections thats the whole point of insulation !!
!!!

I'm no electronics expert but i think you will find there are lots of grounded connections not least in EMI filters. If you think of computers or any electronic wizardry etc they have an earth leakage not because they are faulty but because they are designed to work that way.

 

[Golden_Boy]

I'm no electronics expert but i think you will find there are lots of grounded connections not least in EMI filters. If you think of computers or any electronic wizardry etc they have an earth leakage not because they are faulty but because they are designed to work that way.

I agree but filters are mainly parallell capacitors and series inductors. there is no DIRECT cotact with "earth" appart from the leakage you mention that would still exist no matter which way round the supply was applied.

 

[Golden_Boy]

Just to put this to bed.....

ANY ac appliance will work correctly when supplied by a 1:1 mains isolation transformer ?


If this is true then all these "polarity" statements fall by the wayside....

 

[Sintra]

Alot of other countries don't care about polarity all they do is use a double pole overcurrent protective device

 

[Golden_Boy]

Alot of other countries don't care about polarity all they do is use a double pole overcurrent protective device

My case rests.....................

 

[pushrod]

I agree but filters are mainly parallell capacitors and series inductors. there is no DIRECT cotact with "earth" appart from the leakage you mention that would still exist no matter which way round the supply was applied.

so there is a contact to ground/ earth (through capacitors) that allows very small currents to flow to earth - that is the only point i was making. Certainly not making any reference to polarity - in fact, if you read through the whole thread you will see that i was the first person to question the dubious symptoms that were being given to reverse polarity.

 

[Golden_Boy]

so there is a contact to ground/ earth (through capacitors) that allows very small currents to flow to earth - that is the only point i was making. Certainly not making any reference to polarity - in fact, if you read through the whole thread you will see that i was the first person to question the dubious symptoms that were being given to reverse polarity.

sorry

 

[andyb]

" There are 10 types of people in this world - those who understand binary, and those who don't "

That's the funniest thing that I've read for a long time.

 

[Mark42]

I'm no electronics expert but i think you will find there are lots of grounded connections not least in EMI filters. If you think of computers or any electronic wizardry etc they have an earth leakage not because they are faulty but because they are designed to work that way.

Yes, and that earth leakage is why there are pages of guidance about increasing the CSA of protective conductors in environments which have a lot of Switch-Mode Power Supplies, like in multiple-computer offices.

I understand that the bits which cause all the trouble are, indeed, EMI/RFI filters.

If filter circuitry is connected between L & N, with for example, the centre junction of two capacitors in series grounded, connection ‘polarity’ is clearly irrelevant.

But if there is some kind of filter circuit between Live only and ground the connected ‘polarity’ might matter I suppose, in that if ‘polarity’ were reversed, the interference filter would not function. The device would then be non-compliant and may feed noise back into the mains, but it would still work.

And I’m surprised that no one has said we should endeavour to ‘Reverse the polarity of the neutron flow’. It’s been a long time.

 

[Risteard]

I'm not disputing that, What I am saying is that there are no AC appliances that will not run correctly ( safety appart ) from an AC supply no matter how it is connected.. Unless someone knows better? Otherwise how does an appliance containg a mains transformer ( wound NOT switch mode) work at all?

Yes I agree with that for a single phase appliance. Only a three phase appliance can be reversed through rotation of the phases. The windings would have to be altered for a single phase motor.

 

[aryan9494]

Apologies for intruding on your website - I am NOT an electician!! I would like some advice - a couple of weeks ago a MeterPlus employee came to fit a new meter in my house - he spotted a fault - said it was reverse polarity - the whole house was affected & told me to get an electrician to sort the problem. To cut a long story sort the problem was identified yesterday as aNEDL problem arising from underground cabling in the village 5 years ago. Basically I was told that the tails to the box on the outside of my house had been wrongly connected causing the reverse polarity. I would like to know what if any risks this has posed to me & my family over the last 5 years but more worryingly if the instalation was wrong to my property what about the rest of the village? Any comments or observations would be most welcome

hi
with reference to your reverse polarity issue the fear of your family affected is vague. the actual problem lies when operate any electrical device and switch it off literally but the phase is present there.
regards
aryan9494

 

[Scud]

Housewife, if you feel that your DNO is not acting on your complaint, you can find out how to approach the regulators at http://www.ofgem.gov.uk/Media/FactSheets/Documents1/changestoconsumer.pdf

 

[davelerave]

Very few in the domestic side of things and it would depend on who made it and how. If you were suffering from that sort of thing then you would notice for instance the hoover would be blowing instead of sucking.

What I would suggest if you are concerned at all let us know what your closest town is (not your address) and perhaps one of the forum members can come round and explain everything to you and put your mind at ease.


Chris

sorry for re-hashing this-have you ever seen a hoover blowing

it wont happen anyway

major hazard anyhow all the installation protective devices will be in the neutral conducter


L-E fault could travel back to a trafo if circuit isn't rcd protected