Advice on electrics understanding

I've put some photographs of my consumer unit etc at the following address:

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'm just trying to make sure I understand what's going on - could anyone confirm my understanding and fill gaps in my understanding.

What I see is:

  1. Meter connected to a 60 amp circuit breaker (is that right? is an mcb? it's not an rcd is it?) There's an additional one to its left not connected up - this was for an old storage heater system I believe)
  2. Circuit breaker (if that what it is) connects to some from of distribution box connecting on left to RCD for electric shower circuit, and on the right connecting to consumer unit on top right of main picture.
  3. In consumer unit there's fused circuits for: 1 30 amp radial for cooker circuit (connects to cooker dual-pole plus 13 amp socket), 2 30 amp ring circuits for power, 3 5 amp lighting circuits, and 1 15 amp circuit for immersion heater.

Am I anywhere near????

Graham

Reply to
Graham Dean
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It looks like an MCB, certainly not an RCD - Though it might just be a basic 60amp switch/isolator

Your description appears to be spot on judging by the photographs alone. Age of the main part of installation somewhere between 1965 and

1979-ish, with the RCD installed in the past ten years or so.
Reply to
Harry Bloomfield

Thank you - I feel a little happier now! (I think...) I think it may be an mcb as it's got a yellow test button in lower middle which breaks circuit on pressing?

This leads on to two further questions - (1) should I really replace the mcb between the meter and distribution unit with an RCD?, (2) the cooker radial circuit is unused presently, but the dual-pole / 13 amp is absolutely in the right place in the kitchen to use as a starting point for a spur for a double-gang socket - is it possible to dothis in any way, through a fused fcu eg? If not, can I easily convert the dual-pole etc to a double-gang 13 amp itself?

Graham

Reply to
Graham Dean

Are the two yellow dots just dots or buttons? If they are buttons then they could be voltage operated ELCBs.

Reply to
Fred

Hi Fred,

They're buttons - i.e. press here to test type of thing.

Graham

Reply to
Graham Dean

I think that these might be old style voltage operated ELCBs.

Do you have a TT incoming supply? In other words, does it arrive by overhead wires and you have an earth rod or is there some other arrangement? If it is a TT supply, then an ELCB was the old way of providing a measure of protection in case of earth leakage. THe present way with a TT supply is to use a 100mA RCD with time delay at this position. You would then normally have a split consumer unit with a 30mA RCD part way across. Then circuits needing 30mA RCD protection such as downstairs and outside circuits would go downstream of this and others such as lights upstream (i.e. between the 100mA and

30mA breakers.

To be honest, considering the age of the CU and the rest of the components, I would be inclined to rip the lot out and put in a new DIN rail consumer unit like an MK Sentry. That way, everything could be housed inside the box for a much neater installation. You can get up to 20 way ones. THe two RCDs are 2ways each leaving 16 breaker positions which should be enough for most installations.

However, if you are going to swap ELCB for RCD etc., (assuming it is a TT system) then the earth rod etc. needs to be checked and measured with proper test gear. If you are going to DIY it, you would need to arrange a building notice and inspection anyway to comply with Part P of the Building Regulations.

If it's not a TT system, but TN-S (earthing via sheath of underground cable) or TN-C-S (aka protective multiple earth or PME) then you don't need an RCD between supply and CU, but you do for certain of the circuits as described above.

You can do either. However, the circuit MCB must be reduced to 20A if you wire on from the existing outlet in 4mm^2 cable or 16A if you use 2.5mm^2.

However, there may be a practical issue of fitting the cables into the sockets. They are normally designed for up to three possibly 4x

2.5mm^2 cables.

Reply to
Andy Hall

system? I.e. what is to the left of the first pic?

The meter is feeding an old voltage operated Earth Leakage Circuit Breaker (ELCB) - the rightmost one of the pair. These detect current flowing to earth and cut the supply. The test button ought to trip the device if pushed. I can't see anything connected to the top of the left hand one.

Ah, that would explain it ;-)

This in known as a "Henley Block" (after a company associated with making them) or a "Service Connector Block". As you susspect it is just a high current rating junction box designed for meter tails. It is splitting the supply into two sub mains. One goes off to the Wylex rewireable CU, the other to what looks like a small CU added on for a high current device - a shower typically.

OK yup

Yup pretty much. It would be handy to see the head end (i.e. where the power comes in to work out what type of supply you have).

Reply to
John Rumm

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