TNS earthing conductor

[rainydays]

Can anyone tell me if there is a minimum size required for the earthing conductor on a TNS system or do you just verify it`s adequacy using the adiabatic equation.

Many thank`s

 

[gordy71]

I guess u are talking about the main earthing conductor? This should be 16mm the same as a PME installation. But you could do a pfc test otherwise to see if the earth is technically adequate i guess?

 

[batty]

Should be 16mm for 25mm tails but when earth is brazed onto sheath maybe a lot less but as long as reading is low enogh should not be a problem. Generally will take cable into earth block and then 16mm to cu.

Batty

 

[Evans Electric]

Just use 16mm.

 

[rainydays]

My boss is a tight git and questions with justification everything i do if he has to spend any money.

I would have just liked to justify what i was doing in black and white

 

[tom1]

depends on meter tail size, but its most likely 16mm

if u had 10mm tails then u could use 10mm main earth but some distributers may want 16mm minimum. 16mm, 25mm and 35mm tails all need 16mm main bond