voltage reading on the nuetral

[Rockomuir]

Hello all,

Been to my local campsite to fit a hairdryer in the toilet blocks. Before starting works i ran through a few basic checks as the installation is prettry old. I checked the voltage at the main switch at the board. I got a reading of 216v phase and 10v on the neutral. Has anyone got any suggesstions as to why i would have 10v on the neutral. The supply for the toilet block is a long run from the cutout so i am expecting so volt drop.

 

[Farmelectrics]

Induced voltage possibly

 

[Moses]

Hello all,

Been to my local campsite to fit a hairdryer in the toilet blocks. Before starting works i ran through a few basic checks as the installation is prettry old. I checked the voltage at the main switch at the board. I got a reading of 216v phase and 10v on the neutral. Has anyone got any suggesstions as to why i would have 10v on the neutral. The supply for the toilet block is a long run from the cutout so i am expecting so volt drop.

Load current in the N-wire produces voltdrop.
But 10V is on the high side.

 

[Rockomuir]

Would this stop me from performing an rcd test and struggle to get a zs reading. What realistically could i do to improve this ?

 

[Jimmy Boy]

Hello all,

Been to my local campsite to fit a hairdryer in the toilet blocks. Before starting works i ran through a few basic checks as the installation is prettry old. I checked the voltage at the main switch at the board. I got a reading of 216v phase and 10v on the neutral. Has anyone got any suggesstions as to why i would have 10v on the neutral. The supply for the toilet block is a long run from the cutout so i am expecting so volt drop.

A Hair Dryer not Hand Dryer ? It's been yonks since I camped they have Hair Dryers now things have moved on

 

[Rockomuir]

50p for three minutes

 

[Jimmy Boy]

50p for three minutes

Bloody Hell lol ! I assume you will carry this out using the format of a minor electrical work certificates so as long as you comply with those requirements I doubt you have owt to worry about, your not doing a PIR !

 

[Moses]

Would this stop me from performing an rcd test and struggle to get a zs reading. What realistically could i do to improve this ?

NO. and

No. and

depends how much you want to spend?

to improve your Zs, ask the DNO to upgrade the supply and convert it to TN-C-S
Install bigger cables for your final circuit.
Install bigger cable for your earth cable.

 

[Knobhead]

As Moses has said, volt drop in the neutral can cause a voltage rise to earth.

I’ve tried to make this drawing as clear as I can.

View attachment 12794

 

[Moses]

As Moses has said, volt drop in the neutral can cause a voltage rise to earth.

I’ve tried to make this drawing as clear as I can.

View attachment 12794

Tony is that the same DWG as the other day?????

You couldn't have done an other one?????

 

[Knobhead]

OK I hold my hand up. I never delete a drawing once done. You never know when you'll need it again.

 

[Jimmy Boy]

OK please explain the physics behind the drawing I don't get it

 

[telectrix]

as i see it, and i may be wrong, in a circuit under load, there is a certain volt drop. this VD is on the L and N, but the E is still at 0v. so there will be a small voltage differential between the N and E, relative to the VD of the circuit,

 

[Jimmy Boy]

OK I hold my hand up. I never delete a drawing once done. You never know when you'll need it again.

Didn't know Abu Hamza was a spark.Sorry couldn't pass on that one..

 

[telectrix]

he may not be but i vote him as a prime candidate for 2000v.

 

[Jimmy Boy]

How many Kv do you get through a HT on a Quad bike coil ? I split a HT circuit other day while it was running I was dancing around like a crack head with St Vitus dance much to the amusement of my 19 year old kid..FK me it hurt

 

[Silly Sausage]

Didn't know Abu Hamza was a spark.

He's not...

 

[Silly Sausage]

OK please explain the physics behind the drawing I don't get it

It's just 3 resistances in series, each one drops voltage across it.

Uo = Supply voltage
R1 = Resistance of Line conductor
Rn = Resistance of Neutral conductor
RL = Resistance of Load

Voltage across Line V1 = Uo * (R1/(R1+RL+R2))

Voltage across Load VL = Uo * (RL/(R1+RL+R2))

Voltage across Neutral Vn = Uo * (Rn/(R1+RL+R2))

V1 + VL + Vn = Uo

 

[telectrix]

How many Kv do you get through a HT on a Quad bike coil ? I split a HT circuit other day while it was running I was dancing around like a crack head with St Vitus dance much to the amusement of my 19 year old kid..FK me it hurt

HT from coils is in the region of 15kV.

 

[Had8Lives]

Check the connections at the main cutout end and look for joins and check the cable size. Your hair dryer may not operate properly on 214V.

 

[Guitarist]

How long is the supply cable and what size is it?

 

[Jocktrician]

I found this site whilst researching another matter, (Newbie), but isn't the case of the low phase voltage and apparently high neutral voltage part of the same argument about exporting PME?, induced voltage (no load) can increase earth voltage relative to true earth and thus is the distribution system earth at the same potential as the true earth at the toilet block. The use of a local earth rod will certainly draw down the earth-true earth potential (if one exists), this and and the volts drop (as previously explained) would assist the neutral 'drifting' to a higher level. I believe the solution is check the earthing and run a quick calc on voltsdrop based on max current draw.

Doing both should give you the comfort that the system is all ok, and if it's a rural site then the cable may simply be undersized. Besides, isn't the campfire for both these purposes!