Cable calculation

[Deleted member 26818]

As far as I am aware, the ESQCR prohibits the use of TN-C within an installation connected to the public network.
As such any connection to the PEN conductor is made outside of the installation.

 

[Nigel]

Anyway. As I stated - a TN-C-S is still a TN-C so the regulation is valid.

 

[Deleted member 26818]

Anyway. As I stated - a TN-C-S is still a TN-C so the regulation is valid.

Not sure what that means.
TN-C-S is allowed for agricultural installations.

 

[Nigel]

Not sure what that means.
TN-C-S is allowed for agricultural installations.

Not according to that reg.

 

[Simon Burton]

Anyway. As I stated - a TN-C-S is still a TN-C so the regulation is valid.

Yeah i agree they are essentially the same

 

[Simon Burton]

Not sure what that means.
TN-C-S is allowed for agricultural installations.

Tncs cannot be used.

 

[Deleted member 26818]

Not according to that reg.

Sorry, doesn’t say that at all.

 

[Nigel]

Sorry, doesn’t say that at all.

Yes it does.

 

[Deleted member 26818]

If either of you two actually want to look at the Regs, you will note that TN-C is where all of the system uses a PEN conductor and TN-C-S is where a PEN conductor is used only in part of the system.
Where TN-C-S is used the part of the system that uses a PEN conductor is on the supply network.

This is really basic stuff.
I’m not surprised someone who believes a 100A switch will trip doesn’t understand, but I am suprised at Essex.

 

[Simon Burton]

Sorry, doesn’t say that at all.

Reg 705.411.4 says a tnc shall not be used. Other words a PEN conductor cannot be used. Meaning seperate earth shall be used, example tt sytem.

 

[westward10]

Reg 705.411.4 says a tnc shall not be used. Other words a PEN conductor cannot be used. Meaning seperate earth shall be used, example tt sytem.

You are not using TN-C because the neutral and cpc are separate through the consumers installation.

 

[Simon Burton]

If either of you two actually want to look at the Regs, you will note that TN-C is where all of the system uses a PEN conductor and TN-C-S is where a PEN conductor is used only in part of the system.
Where TN-C-S is used the part of the system that uses a PEN conductor is on the supply network.

This is really basic stuff.
I’m not surprised someone who believes a 100A switch will trip doesn’t understand, but I am suprised at Essex.

I see where your coming from but lets say you loose your pen conductor at the very source from the transformer. Not at the point at which you make it a tncs when connecting your earth. But the very source. If that pen conductor goes down, where is your mean of earth?

 

[Deleted member 26818]

No you cannot use a PEN conductor, just the same as you cannot use a PEN conductor in your house.
Doesn’t necessarily mean TT is the only option.

What really matters, is whether PME can be used.
In some circumstances it can be used, though it would be advisable to install an earthed metallic grid in the ground where livestock are to be kept.

 

[Simon Burton]

No you cannot use a PEN conductor, just the same as you cannot use a PEN conductor in your house.
Doesn’t necessarily mean TT is the only option.

What really matters, is whether PME can be used.
In some circumstances it can be used, though it would be advisable to install an earthed metallic grid in the ground where livestock are to be kept.

I agree PME is the way to go, like you say especially if livestock can come into contact with the installation

 

[westward10]

Have you sized this cable yet.

 

[Deleted member 26818]

I agree PME is the way to go, like you say especially if livestock can come into contact with the installation

I give up.

 

[Nigel]

If either of you two actually want to look at the Regs, you will note that TN-C is where all of the system uses a PEN conductor and TN-C-S is where a PEN conductor is used only in part of the system.
Where TN-C-S is used the part of the system that uses a PEN conductor is on the supply network.

This is really basic stuff.
I’m not surprised someone who believes a 100A switch will trip doesn’t understand, but I am suprised at Essex.

A picture to help you.

 

[Nigel]

You are not using TN-C because the neutral and cpc are separate through the consumers installation.

The third letter means how the earth and neutral are linked at the transformer.

T = earth
N = Neutral
C = Combined.

This is true of both a TN-C and a TN-C-S. the S is for ‘seperate’ as the earth is then seperated from the neutral within the installation.

 

[westward10]

Why do you therefore insist they are the same.

 

[Nigel]

Why do you therefore insist they are the same.

I do not insist they are the same. I insist that a TN-C-S is a TN-C but then seperated. A TN-C cannot be a TN-C-S.