TT supply type

[domestic spark]

When making a supply type TT what is the smallest cpc you can use from the rod to the MET thanks I'n advance. From orign to DB 25mm tails. Bs1361 type 2 main fuse. 100a

 

[telectrix]

all depends on the Ze and PFC. as long as the cable will stand the PFC. say you had a Ze of 20ohms, PFC would be 11.5A. generally 6mm is sufficient.

 

[domestic spark]

If i installed 10mm what's my maximum figures, to look for, for ZE and PFC thankyou

 

[malcolmsanford]

You can if you wish and calculate as Tel said, go down as low as 2.5mm as per regulation 543.1.1 if it is mechanically protected, if that is what the Adiabatic equation gives you.

Think you find that most sparks will opt for either 4mm/6mm. Even if the calculations came up to under 6mm I would normally not go less than 6mm go with that on a TT, but that is just my opinion.

 

[telectrix]

if you use 10mm i wouldn't worry unless you got a ridiculously low Ze and high PFC. e.g. Ze below 5ohms. PFC above 50A

 

[domestic spark]

Thankyou

 

[Chr!s]

Is the cable going to be buried?

 

[domestic spark]

Is the cable going to be buried?

No it isn't going to be buried

 

[telectrix]

6 or 10, depends on which is easier to find in the rat's nest i call my van.

 

[domestic spark]

if you use 10mm i wouldn't worry unless you got a ridiculously low Ze and high PFC. e.g. Ze below 5ohms. PFC above 50A

At present with parallel paths inplace and taking bond from services ZE 0.30ohms and pefc of 695a! Haha

 

[malcolmsanford]

Ze Parallel path isn't that an oxymoron.

 

[Guest 004]

well if you use a 30mA protection device, you can in effect have 1667 ohms, and it would still work! so you could in fact just place a nail in the wall with a 1mm cable attached to it! haha, it is fact, but not recommended.

 

[domestic spark]

well if you use a 30mA protection device, you can in effect have 1667 ohms, and it would still work! so you could in fact just place a nail in the wall with a 1mm cable attached to it! haha, it is fact, but not recommended.

hmmmmmm

 

[Guest123]

My local council insist on a minimum of 16mm regardless.

They just cover themselves incase the conductor is buried for any length.

 

[Guest 004]

Local councils, dont you just love them. Failed sparkies in most cases