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- 1 May 2005
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Hello,
I have a 9.5kW electric shower connected as follows:
1) 6mm2 cable from consumer unit to isolator switch (pre-existing)
2) 10mm2 cable from isolator switch to shower (I fitted this larger cable)
3) protected with 30amp MCB (pre-existing)
4) No RCD
This arrangement is tripping the MCB after about 3-7 mins due to (I am fairly sure) the 6mm2 cable getting hot. The shower needs a bigger MCB and bigger cable.
What I want to do is uprate the 6mm2 cable to 10mm2 and also uprate the MCB to 45amps.
My main question is:
1) is this safe and straightforward to do or are there other considerations?
a) Does the MCB solely protect the cable or does it have any other purpose?
b) What do I need to consider at the consumer unit side for such a replacement?
c) Do I need an RCD?
For additional info, my consumer unit actually seems to be 2 units (installed roughly 21 years ago):
The first larger box says "Total load not to exceed 60amps" - in this are 4 MCB's rated at 5, 30, 30 and 30amps each.
The second smaller box says "Total load not to exceed 45amps" - in this are 2 MCB's rated at 15 and 30amps each.
Thanks very much in advance for any help.
Cal
I have a 9.5kW electric shower connected as follows:
1) 6mm2 cable from consumer unit to isolator switch (pre-existing)
2) 10mm2 cable from isolator switch to shower (I fitted this larger cable)
3) protected with 30amp MCB (pre-existing)
4) No RCD
This arrangement is tripping the MCB after about 3-7 mins due to (I am fairly sure) the 6mm2 cable getting hot. The shower needs a bigger MCB and bigger cable.
What I want to do is uprate the 6mm2 cable to 10mm2 and also uprate the MCB to 45amps.
My main question is:
1) is this safe and straightforward to do or are there other considerations?
a) Does the MCB solely protect the cable or does it have any other purpose?
b) What do I need to consider at the consumer unit side for such a replacement?
c) Do I need an RCD?
For additional info, my consumer unit actually seems to be 2 units (installed roughly 21 years ago):
The first larger box says "Total load not to exceed 60amps" - in this are 4 MCB's rated at 5, 30, 30 and 30amps each.
The second smaller box says "Total load not to exceed 45amps" - in this are 2 MCB's rated at 15 and 30amps each.
Thanks very much in advance for any help.
Cal