Indicator light for cooker hot plate

In the middle of last night I noticed, for the first time, the red indicator light for the single electric hotplate on the cooker control panel.

We've spent 280 nights in the van in the 22 months we've had it: the light is just below the glass hob top where we leave our water glasses for night use but we have neither of us seen the light before. Last night, even without my glasses on, it was glowing very strongly and impossible  to miss.

Is is usually on all the time ? Could it have been off for 22 months and just switched on at random last night ?  It seems quite stable and is not flickering. We've not used the electric plate for ages but it is plugged in and switched on at the plug below the cooker.

We are puzzled as to how we've managed to miss it...if we have !

The light comes on if the live and neutral in the 230v supply are reversed.  Where are you?

Whew Peter ! You're absolutely right and we are amazed and very grateful.

We are at Cabo de Gata: we arrived 2 nights ago, plugged in and, as the mains tester indicated reversed polarity, put in the polarity changing lead.  Ten minutes later we moved to the next pitch and simply plugged back in again to the next socket, same bollard, for our new pitch. This is clearly normal polarity but I did not check it as  I assumed, being the same bollard, it would be same polarity. 

All is now well, the polarity is now normal and we hope not to see the red light tonight. 

Many thanks and how very lucky we are to have your skill and knowledge to hand.

Q

Quilter wrote: I assumed, being the same bollard, it would be same polarity. 

It is not at all unusual to find the 'polarity' vary from socket to socket in the same bollard.

Enjoy your trip. I'm sure the weather will be better than the torrential rain we had at Moreton in Marsh over the weekend and the gales at Cambridge on Monday!

Thanks Peter: we don't normally move pitch quite so quickly but, having paid for a service pitch we then found we couldn't get the hose in in the first one.

It's been raining here this morning and blowing a gale since we arrived. It did the same last year. The Cabo is supposed only to get 5 days rain a year but it is all timed to be when we are here.

Warm though !

We also have had the glow with reversed polarity, although I would only describe it as a slight glow, much dimmer than the normal indication when the hob is actually switched on.

This is quite a useful facility as it gives an indication of reversed polarity without all the mucking about with testers

Peter Brown wrote:The light comes on if the live and neutral in the 230v supply are reversed.  Where are you?

what are the chances of me remembering that when I have the need?

I'll put it in the memory bank and hope not to need it.

Thank you.

1.So if you havent got a hot plate light, how do you know if you have got reverse polarity.

2. Is it dangerous.

3. Am I going to wake up dead if i have got it.

4. Why is mptorhoming so complicated.

5. How naive did I have to be to buy one and think I could just drive off into the sunset and enjoy myself..lol

in theory reversed polarity CAN leave metal bits live instead of earthed. However, in practice unless you are poking metal things in places that they shouldn't be there is no real problem. Other safety circuits will take over and protect you.

Dave (above) is absolutely right.

Reversed polarity is a misnomer for a start. How can you talk about polarity when the direction of the current reverses 50 times per second??

In simple terms all it really means is that with "reversed polarity" the switch on an appliance is at the exit end of the current flow, so if you open it up and poke around inside you may well get a shock. (With the "polarity" the correct way round, the switch on the appliance would be right at the entry of the current flow, so switching it off would make all the internals safe to touch)

The above paragraph assumes Darwinian stupidity however   , since no-one with a grain of common sense would fiddle around inside an electrical appliance without first unplugging it.

This is not quite the whole picture, but if fingers are kept out of appliances unless they are unplugged, the likelihood of having a problem is miniscule.

Dave

P.S. I am not an electrician, but the above was confirmed by my neighbour who is very highly qualified - also a motorhomer, and he never bothers to check the "polarity" when abroad.

Sorted, thats another one of the things to worry about that I dont actually have to worry about.

Cheers Dave and Dave.

Are there items that we use that are polarity sensitive ?
eg. hairdryers (not me ...if only I had some to dry !!)  Tv's,  ect..

I don't think so. As (the other) Dave said, the polarity reverses 50 times a second so there isn't really a correct polarity.

dbroada wrote:I don't think so. As (the other) Dave said, the polarity reverses 50 times a second so there isn't really a correct polarity.

But, If I put a current through an electric motor, I thought that polarity denotes which way the motor turns ?  ie.  hairdryer sucks, or blows. , same with a vacuum cleaner. ?

a DC motor will change direction if you reverse the polarity but an AC one won't. They may have a DC motor with a rectifier but this will be configured to send the motor the direction required.

N should be at earth potential and L plus and minus about 300V. If you reverse them the fuse in the plug and the switch will be in the wrong lead. This means that when switched off the appliance is still "live"inside and the fuse which has s part of the fault protection in a three wire connection will not work. This is normally not important but might be with older equipment.

There are some applications that will not work at all with 'reversed polarity'. One which I have experienced was when using the Eberspächer heater in our Duetto on mains. With reversed polarity, the electric heater part of the Eberspächer simply would not work at all and the heater would only run on diesel (even though mains had been selected).

The bottom line with reversed polarity is simple: if you like a simple, easy life in your motorhome, then make sure that your polarity is correct at all times. If you like surprises, then be blasé and don't ever check; who knows one day you may get one.

So how do I find out if the polarity is reversed, if it is what am i supposed to do about it, maybe turn the battery  upside down. In the absence of an electrical engineering degree I think i might just drive it off a cliff !

Where are the verifiable statistics? I would be very interested to see them if anyone can point the way.  

There's plenty of speculation and ill informed scare stories around on all the forums, and they don't help newcomers to motorhoming - they just frighten them needlessly!! I have never heard of a single instance where someone has been in any way harmed by "reversed polarity" - unless they were being a complete idiot! Come to think of it, I've never heard of an electrocuted idiot blaming his mishap on reversed polarity!!

You are more likely to be gassed in the South of France!!  

Dave


P.S. To any newcomers. It was a joke!! Do not be alarmed in the slightest.

Read this -
http://www.rcoa.ac.uk/news-and-bulletin/rcoa-news-and-statements/statement-alleged-gassing-motor-vehicles

It is very rare that reversed polarity will cause dangers on a modern van. The RCB gives full protection with correct or reversed polarity. Most accessories will be double insulated which gives protection against a no-earth installation. In the UK neutral is connected to earth at the local substation and an ac meter across N&E will show around 10v. L&E will be about 230v.
in Europe  neutral is not connected to earth so, in effect, both neutral and live fluctuate between 110v and -110v
In the UK the hotplate neon will light dimly with reversed polarity. In Europe it may light dimly irrespective of polarity.
I have ceased to worry, reckoning that the RCB  gives full protection.

If you have the inclination and time then an interesting and illuminating discussion here:

http://forums.outandaboutlive.co.uk/forums/Motorhomes/Motorhome-Matters/Reversed-Polarity-in-France/24028/61/

" Oh let us never, never doubt
What nobody is sure about"

Q

Standards are agreed and laid down for a reason. Ignore them if you wish.

But please tell me what is the point in having them?

Quilter wrote:If you have the inclination and time then an interesting and illuminating discussion here:

http://forums.outandaboutlive.co.uk/forums/Motorhomes/Motorhome-Matters/Reversed-Polarity-in-France/24028/61/

" Oh let us never, never doubt
What nobody is sure about"

Q

A very wordy thread with a lot of verbiage on risks that only apply to old vans without a double pole rcb - which my van has! I found it very supportive of my personal view - but if you do not understand electrics then DO NOT USE EHU IF YOU HAVE ANY DOUBTS ABOUT ITS SAFETY.