Immersion + timer cable size?

[mattyashy]

In another thread I was helped out with wiring a timer that had been wired incorrectly.

I now realise that I need to change some cable that has gone rotten, plus one of the flex cables is just about long enough making it fiddly to wire in.

The current setup is:

Heatae Sadia Megaflo HE + a TimeGuard NTT05 timer for each immersion heater.

The cable runs from the immersion to the timer. And then another from the timer to the isolator switch (all of the cables are currently 1.5mm flex).

The questions:

- Do I replace all the cables with 1.5mm flex?
- Do I replace all with 2.5mm flex?
- Or any other combination?

 

[pete01]

Is the immersion heater 3kw? If so use 2.5mm

 

[mattyashy]

Yep, both are 3kw.

 

[EFLImpudence]

1.5mm² is actually adequate but everybody (except your installer obviously) still uses 2.5mm² because it used to be the requirement with 15A rewirable fuses and progress is a terrible thing.

 

[mattyashy]

1.5mm² is actually adequate but everybody (except your installer obviously) still uses 2.5mm² because it used to be the requirement with 15A rewirable fuses and progress is a terrible thing.

If I can get away with 1.5mm that'd be a godsend - fitting 2 x 2.5mm cables into one terminal on the timer is a bastard