Reverse polarity

[GrumpyGranddad]

Apologies if this is a daft question but I’ve read some of the existing threads on this issue and am still unclear about what needs to be done if reverse polarity is detected at a site. Some say don’t worry about it, some say there is a potential danger when plugging in appliances, some say buy a reverse polarity cable and some say don’t bother.

So,
1. Should I buy a tester and test at every campsite before hooking up the Cali’? (If so any recommendations on a tester - there’s loads on Amazon)
2. If reverse polarity is detected at a site what action is needed and should I buy or make a reverse polarity cable.

Very grateful for any advice on this.

 

[WelshGas]

Apologies if this is a daft question but I’ve read some of the existing threads on this issue and am still unclear about what needs to be done if reverse polarity is detected at a site. Some say don’t worry about it, some say there is a potential danger when plugging in appliances, some say buy a reverse polarity cable and some say don’t bother.

So,
1. Should I buy a tester and test at every campsite before hooking up the Cali’? (If so any recommendations on a tester - there’s loads on Amazon)
2. If reverse polarity is detected at a site what action is needed and should I buy or make a reverse polarity cable.

Very grateful for any advice on this.

Practically - only problematic if you leave something plugged into the Mains supply with a metal casing ( maybe ).
On the Continent Mains appliances have a power switch that disconnects the +tve and -tve supply. UK appliances normally have a power switch that only disconnects the +tve supply.
So, in the case of Reverse Polarity on site a U.K. appliance can be switched Off but could still be Live, unless unplugged.

 

[GrumpyGranddad]

Practically - only problematic if you leave something plugged into the Mains supply with a metal casing ( maybe ).
On the Continent Mains appliances have a power switch that disconnects the +tve and -tve supply. UK appliances normally have a power switch that only disconnects the +tve supply.
So, in the case of Reverse Polarity on site a U.K. appliance can be switched Off but could still be Live, unless unplugged.

Thanks WG but would you still recommend a tester and reverse cable? Have you ever needed them? Can the wrong polarity potentially damage the leisure battery charger (you’ll gather I’m no electrician).

 

[sidepod]

Practically - only problematic if you leave something plugged into the Mains supply with a metal casing ( maybe ).
On the Continent Mains appliances have a power switch that disconnects the +tve and -tve supply. UK appliances normally have a power switch that only disconnects the +tve supply.
So, in the case of Reverse Polarity on site a U.K. appliance can be switched Off but could still be Live, unless unplugged.

No. The California is fitted with a double pole circuit breaker meaning it disconnects both live and neutral in the event of a fault.......just like all the Euro domestic ones.

 

[sidepod]

Oops. Sorry WG misread your post.

 

[TripleBee]

Is this something that only affects UK residents?
You all so worry about plugging something in.
It doesn't matter how you plug in, because it is AC (alternating current = no + and no -).
And appliances with a metal housing should have 3 connections. 2 for the voltage, and one for the earth. This is connected to the body of the van.
In my almost 40 years, I have never had any problems with plugging and unplugging appliances on the continent.

 

[Wildcamper]

I am amazed that a vehicle as expensive as a Cali does not have a switch to reverse the reverse polarity when it is detected. In our conversion the main fuse board is alarmed so it buzzes when reverse polarity is detected, as it was in Ireland last year. Then all you have to do is flick a switch to reverse the reverse polarity to give normal polarity. The trick is to remember to switch it back when you leave.

 

[Wesel]

This concern does not exist on the continent. No one is talking about it here.

 

[Stoneybroke]

I have one of these in my cable bag.

LAP 16A Socket Tester 230V AC - Screwfix

Order online at Screwfix.com. Pocket-sized, mains socket tester with LED indicators to show condition of circuit sockets. FREE next day delivery available, free collection in 1 minute.

www.screwfix.com

 

[sidepod]

I am amazed that a vehicle as expensive as a Cali does not have a switch to reverse the reverse polarity when it is detected. In our conversion the main fuse board is alarmed so it buzzes when reverse polarity is detected, as it was in Ireland last year. Then all you have to do is flick a switch to reverse the reverse polarity to give normal polarity. The trick is to remember to switch it back when you leave.

Have you read any of this thread?

 

[Loz]

Is this something that only affects UK residents?
You all so worry about plugging something in.
It doesn't matter how you plug in, because it is AC (alternating current = no + and no -).
And appliances with a metal housing should have 3 connections. 2 for the voltage, and one for the earth. This is connected to the body of the van.
In my almost 40 years, I have never had any problems with plugging and unplugging appliances on the continent.

In the UK. the neutral is bonded to earth so only one live which is switched if the polarity is correct.

 

[TripleBee]

In Belgium, there are almost no houses with full 3x380V + N electricity.
Most only have 3x220V, or even 1x220V (make that 230V now).
This should mean that every house in the UK has what we call industrial electrical connection.

If the electricity from the 3x220V comes from a triangular connection, you don't even have the N line. This means that every line (phase) is live.
If you have electricity from a star connection (3x380V + N) then you have a neutral line.


Can you confirm that every house in the UK has 3x380V + N ?

 

[andyinluton]

I am amazed that a vehicle as expensive as a Cali does not have a switch to reverse the reverse polarity when it is detected. In our conversion the main fuse board is alarmed so it buzzes when reverse polarity is detected, as it was in Ireland last year. Then all you have to do is flick a switch to reverse the reverse polarity to give normal polarity. The trick is to remember to switch it back when you leave.

Why bother reversing the reverse polarity. Unless you are using 1960s metal cased appliances or trying to repair something whilst it is still plugged in & relying on the appliance on off switch, you are worrying about a problem that doesn’t exist.
All modern chargers, kettles, hairdryers and the like will be fine

 

[TripleBee]

In the UK. the neutral is bonded to earth so only one live which is switched if the polarity is correct.

I really hope your blue N line is not connected to earth, and leave that for the yellow/green wire.

 

[GrumpyGranddad]

Wow, you lot know your stuff
Anyway, I’m now reassured that I won’t blow up my Cali’ regardless of the hookup supply polarity and I won’t electrocute myself as all appliances are modern.
Thanks all.

 

[sidepod]

In the UK. the neutral is bonded to earth so only one live which is switched if the polarity is correct.

Not locally on a campsite. Always TT (not TNC-S) so separate earth rod.

 

[larrylamb]

Can you confirm that every house in the UK has 3x380V + N ?

No, they don't here.

 

[Loz]

In Belgium, there are almost no houses with full 3x380V + N electricity.
Most only have 3x220V, or even 1x220V (make that 230V now).
This should mean that every house in the UK has what we call industrial electrical connection.

If the electricity from the 3x220V comes from a triangular connection, you don't even have the N line. This means that every line (phase) is live.
If you have electricity from a star connection (3x380V + N) then you have a neutral line.
View attachment 65386

Can you confirm that every house in the UK has 3x380V + N ?

Only the very latest new houses who require 3phase for rapid car charging. 3 phase plus neutral.

 

[B J G]

I really hope your blue N line is not connected to earth, and leave that for the yellow/green wire.

A few year ago my mains Electrical Supplier (not the one that I buy electrical power from) cut the old green/yellow earth at the meter/input area and did as @Loz says, connected to neutral incoming line.

 

[sidepod]

I think you mean 3x 115

A few year ago my mains Electrical Supplier (not the one that I buy electrical power from) cut the old green/yellow earth at the meter/input area and did as @Loz says, connected to neutral incoming line.

Yes this is fine if the supplier dictates there is TNC-S available in your area.
Regs state caravan sites are not to have exported earths and must have separate earth rods.

 

[Pd.]

In the UK we use a delta star conformation which is nomi

I really hope your blue N line is not connected to earth, and leave that for the yellow/green wire.

Loz is correct the star point of the transformer is connected to earth and also the neutral. The now common method of electricity distribution supply cables in the UK does not have an earth cable but uses the Neutral conductor within the cable for the return path of any fault current. This is called a PME (TN-C-S) system and has been an ongoing change for over 30 years. However not all installations are allowed to have this system caravan and camping sites being one of them.

The reason that the neutral line is connected to the star point (and the Earth) is that it acts as a reference point to keep the voltage in each phase constant at 220/240 if its not or comes detatched then the voltage in each phase can vary depending on load. It does happen infrequently in the supply industry and results in damaged equipment when it does. It also acts as the return path for both the neutral and fault current.

The transformer star point is connected to earth via a system of earth cables and rods to form a low impedance providing a return bath for fault current back to its 'scource' transformer if necessary. Therefore allowing protection devices to operate.

Now back to the question if the bodywork of the van is connected via an earth to the incoming neutral conductor than cross polarity will make the van bodywork live (I don't know if it does maybe Loz would know) however I think that it is prohibited under the ESQC Regulations. Altough the circuit will have overload proction i.e a fuse or circuit breaker the circuit also has short circuit protection and this is much faster acting than a fuse a RCCD operates on the balance principle of what flows in must flow out and if there is a mismatch by a small amount typically 30mA than it operates cutting the supply and this feature is not polarity sensative. So even with cross polarity the protection provided by the RCCD operates in the same way. In the unliklt event taht a fault energises metel parts which are touched and you complete a circuit to earth then current will flow via the general mass of earth back to the supply transformer and cause the necessary imbalance to make the RCCD opearte.

Having said all of that should I be on a site with cross polarity then I would change the conection to match what is required.

I wonder however how often the RCCD in the van is tested?

I hope that the above helps to explain things Pd

 

[sidepod]

I wonder however how often the RCCD in the van is tested?

Not easy to do given that there is another one immediately upstream at the hook up point.
In order to test it properly (1/2 x current/1x current and 5x current 0 and 180 deg) you would need a dedicated supply without any other RCD.

 

[TripleBee]

So from what I hear in this thread, it is normal in the UK to connect the blue and green/yellow cable to each other and to earth?
In the rest of Europe you are creating a direct short circuit.

This means connecting N and PE to earth. In that case this appliance will never work, and your circuit breakers will turn off.

In Europe, you have 380V between L1,L 2 and L3. 220V between N and L1, L2 and L3. And PE is connected to earth, in case of RCD.

I think I am going to throw my lesson books of electricity away...

 

[Pd.]

It is all a bit strange but essentially yes.

To answer your question a bit further talking about the street supply set up then a typical supply to a house is just L and N there is no earth wire of any type seperate wire or sheath. The cable has a live core and an outer neutral..

As for the house supply Fuses are only installed in the Live. The neutrals are connected to a common neutral bar and the earths to a common earthing bar within the fuseboard

The houseLive supply is conected via the metering equipment and a supply fuse 80/100A to the incoming elecectricity company cable.

The neutral and earth conections from thier conection bars are then conected to the incoming supply company neutral via a conection which also connects to the incoming supply cable. The picture below also shows an earthing conection block but this then goes straight to the incoming supply neutral

3-phase supples are the same but with 3 L supplies.

See image below



Hope it helps in your understanding of how the UK does things

We do still have supplies with a seperate earth circuit and some where an earth is not provided at all,

Kind regards Pd

 

[sidepod]

It is all a bit strange but essentially yes.

To answer your question a bit further talking about the street supply set up then a typical supply to a house is just L and N there is no earth wire of any type seperate wire or sheath. The cable has a live core and an outer neutral..

As for the house supply Fuses are only installed in the Live. The neutrals are connected to a common neutral bar and the earths to a common earthing bar within the fuseboard

The houseLive supply is conected via the metering equipment and a supply fuse 80/100A to the incoming elecectricity company cable.

The neutral and earth conections from thier conection bars are then conected to the incoming supply company neutral via a conection which also connects to the incoming supply cable. The picture below also shows an earthing conection block but this then goes straight to the incoming supply neutral

3-phase supples are the same but with 3 L supplies.

See image below

View attachment 65429

Hope it helps in your understanding of how the UK does things

We do still have supplies with a seperate earth circuit and some where an earth is not provided at all,

Kind regards Pd

You’re missing out those supplies that use the cable armour as the earth. Very common.
The uk has 3 types of domestic supply.