Correct Wire Size For 4.5 Kw Shower Heater?

[Crossy]

Thanks for all the info. Now I just need to plan my schedule of work and buying of materials.

Since you are living in the house and there appears to be little or no grounding, I would get a DIN mount RCD in that space to the right of the main breaker and feed the whole house through it as your number one priority.

[212traders]

Thanks for all the info. Now I just need to plan my schedule of work and buying of materials.

Since you are living in the house and there appears to be little or no grounding, I would get a DIN mount RCD in that space to the right of the main breaker and feed the whole house through it as your number one priority.

What size DIN RCD should I get? Once I put it in, how do I connect the wires?

By rewiring the whole house, my ceiling is made of drywall with aluminum frame as its structure. I don't see a way to get on it without breaking it. It seems that when the house was built, the aluminum frame must have been installed first, then the wiring and then the drywall. Any suggestion on how can I do the rewiring in the attic without breaking the ceiling drywall?

[Crossy]

HomePro carry ABB units, since you have a 50A incomer I suggest a 63A rated 30mA trip RCD such as ABB F202 A-63/0,03 U http://www.abb.com/product/seitp329/056160f1474deb8fc1256f56004c0a66.aspx?tabKey=2&app=9AAG1827&lc=en&cc=TH&cid=9AAC100505&gid=ABB2CSF202101U1630&ev=1568 or similar.

1. To connect it turn off the main switch / incomer (duh), but remember the bottom terminals of the incomer are still live so watch where you're poking things.
2. Disconnect the two wires from the top of your incomer, mark the incomer with L and N (verify with your neon screwdriver just to be sure).
3. Clip the RCD to the DIN rail between the incomer and the breakers
4. Run two short lengths of 10mm² between the top terminals of the RCD and the top terminals of the incomer, make L the right hand side of the RCD
5. Run a new length of 10mm² from the bottom left of the RCD (N) to the neutral bar (remove the crumby bit of cable currently in use)
6. Run a short length of 10mm² between the bottom right of the RCD (L) and the bus bar along the bottom of the breakers (remove the crumby bit of cable currently in use)
7. Check your work
8. Check it again.
9. Turn on the main breaker, turn on the RCD, everything should stay on.
10. Press the Test button, the RCD should trip.

Job done.

You'll need to cut some holes in your ceiling and use bamboo poles to feed the cables through, or get a Thai guy up there, those ceilings are actually amazingly robust.

[wayned]

Sounds like your ceiling is a standard drop ceiling with 60cm2 panels in aluminum frames. The panels can be removed, cut and all wiring done from a ladder below. Picture would be nice!

Edited January 23, 2014 by wayned

[212traders]

HomePro carry ABB units, since you have a 50A incomer I suggest a 63A rated 30mA trip RCD such as ABB F202 A-63/0,03 U http://www.abb.com/product/seitp329/056160f1474deb8fc1256f56004c0a66.aspx?tabKey=2&app=9AAG1827&lc=en&cc=TH&cid=9AAC100505&gid=ABB2CSF202101U1630&ev=1568 or similar.

1. To connect it turn off the main switch / incomer (duh), but remember the bottom terminals of the incomer are still live so watch where you're poking things.
2. Disconnect the two wires from the top of your incomer, mark the incomer with L and N (verify with your neon screwdriver just to be sure).
3. Clip the RCD to the DIN rail between the incomer and the breakers
4. Run two short lengths of 10mm² between the top terminals of the RCD and the top terminals of the incomer, make L the right hand side of the RCD
5. Run a new length of 10mm² from the bottom left of the RCD (N) to the neutral bar (remove the crumby bit of cable currently in use)
6. Run a short length of 10mm² between the bottom right of the RCD (L) and the bus bar along the bottom of the breakers (remove the crumby bit of cable currently in use)
7. Check your work
8. Check it again.
9. Turn on the main breaker, turn on the RCD, everything should stay on.
10. Press the Test button, the RCD should trip.

Job done.

You'll need to cut some holes in your ceiling and use bamboo poles to feed the cables through, or get a Thai guy up there, those ceilings are actually amazingly robust.

As you have suggested that it's best that I re-wired the whole house. If I were to get a larger panel (8 breakers), will this RCD work with the larger panel?

[Crossy]

Yes, provided you get a DIN mount panel (ABB do them, HomePro stock them), you can re-use your incomer and breakers too then.