Extra RCD on off peak F / Obsolete Switch / Economy 7 / Retro fit MCB's

[Paul Silver]

Hi, I'm not an electrician, I wonder if anyone can help me with a few queries.

Q1. Can you explain what this 40A RCD might be for (Off Peak F)?

I have a cartridge fuse board from the standard meter (house built in 1970).
The original heating (fed through the off peak F meter) was obsolete in the late 1980's, and storage heaters installed. The storage heaters are connected to a separate consumer unit (MCB's?) , with a 63A RCD.
What's puzzling to me is that there's a 40A RCD connected between the cartridge board (standard energy) and the 63A consumer unit for the heating (off peak F).

The cartridge fuses are as more or less as expected, 5A lights, 5A lights, 15A immersion (dual supply), 30A sockets, 30A cooker.

If the 40A RCD is turned off everything still works.
Can anyone explain what this RCD might be for/why there might be a connection between the supplies. (It doesn't turn off the dual immersion supply either).

Q2. Removal of old TV supply from henley blocks direct from meter.

It's an end of terrace ex council house, and there used to be one TV aerial outside, with a splitter box supplying the tv signal to the other houses. This was removed years ago, but the supply switch is still connected.
The output from the standard meter connects to henley blocks - routed to both the cartridge fuse board, and the old TV supply switch (so the old switch isn't fused, or connected to the fuse board).

To disconnect this switch, would that be a job for an electrician, or SSE?

Q3 I'm thinking about changing from off peak F to economy 7. SSE weren't particularly helpful in explaining what I need to do, other than get an electrician to swap the supply to the heating from the off peak meter to the standard meter prior to the meter change.
Is it as simple as disconnect from one, and move to the other? Or more complicated?

I'm trying to guesstimate if switching from F to 7 would be beneficial.
Currently 78% of energy use is through off peak F, and 22% standard energy.
However comparing this to economy 7 isn't straight forward, as 2.75 hours of the off peak usage would fall under the standard energy rate for economy 7. Using the washing machine at night might counter balance a bit...
The switch would see a saving of 4p per unit from F to 7,
an increase of 3p per unit for standard energy/day rate,
but possibly a change of 25% energy usage moved from the discounted rate, to the higher rate....

Can't decide if best to stick with F (through SSE), or switch to economy 7 to enable switching supplier for better economy 7 rates down the line...!
So knowing whats involved with preparing the electrics would be helpful in the decision!!!

Q4 Wylex retro fit MCB's
One of the cartridge fuses was replaced with an MCB (about 20 years ago) - Wylex retro fit into old standard range units (and it is a Wylex fuse board!).
Whilst I appreciate fitting a new consumer unit would mean a wiring inspection which would be the best option long term, for now would replacing the rest of the cartridge fuses be a sensible short term move?

 

[davesparks]

Replacing the cartridge fuses with mcbs will offer no better protection, and if the earth fault loop impedance of the circuits is too high then the mcbs may be worse than the cartridge fuses.
The mcbs will provide the convenience of being easier to reset after they have operated.

It's hard to say what the mystery RCD is doing without seeing it, it could be a 24hr supply for the boost element in the hot water cylinder.

 

[Pete999]

Hi, I'm not an electrician, I wonder if anyone can help me with a few queries.

Q1. Can you explain what this 40A RCD might be for (Off Peak F)?

I have a cartridge fuse board from the standard meter (house built in 1970).
The original heating (fed through the off peak F meter) was obsolete in the late 1980's, and storage heaters installed. The storage heaters are connected to a separate consumer unit (MCB's?) , with a 63A RCD.
What's puzzling to me is that there's a 40A RCD connected between the cartridge board (standard energy) and the 63A consumer unit for the heating (off peak F).

The cartridge fuses are as more or less as expected, 5A lights, 5A lights, 15A immersion (dual supply), 30A sockets, 30A cooker.

If the 40A RCD is turned off everything still works.
Can anyone explain what this RCD might be for/why there might be a connection between the supplies. (It doesn't turn off the dual immersion supply either).

Q2. Removal of old TV supply from henley blocks direct from meter.

It's an end of terrace ex council house, and there used to be one TV aerial outside, with a splitter box supplying the tv signal to the other houses. This was removed years ago, but the supply switch is still connected.
The output from the standard meter connects to henley blocks - routed to both the cartridge fuse board, and the old TV supply switch (so the old switch isn't fused, or connected to the fuse board).

To disconnect this switch, would that be a job for an electrician, or SSE?

Q3 I'm thinking about changing from off peak F to economy 7. SSE weren't particularly helpful in explaining what I need to do, other than get an electrician to swap the supply to the heating from the off peak meter to the standard meter prior to the meter change.
Is it as simple as disconnect from one, and move to the other? Or more complicated?

I'm trying to guesstimate if switching from F to 7 would be beneficial.
Currently 78% of energy use is through off peak F, and 22% standard energy.
However comparing this to economy 7 isn't straight forward, as 2.75 hours of the off peak usage would fall under the standard energy rate for economy 7. Using the washing machine at night might counter balance a bit...
The switch would see a saving of 4p per unit from F to 7,
an increase of 3p per unit for standard energy/day rate,
but possibly a change of 25% energy usage moved from the discounted rate, to the higher rate....

Can't decide if best to stick with F (through SSE), or switch to economy 7 to enable switching supplier for better economy 7 rates down the line...!
So knowing whats involved with preparing the electrics would be helpful in the decision!!!

Q4 Wylex retro fit MCB's
One of the cartridge fuses was replaced with an MCB (about 20 years ago) - Wylex retro fit into old standard range units (and it is a Wylex fuse board!).
Whilst I appreciate fitting a new consumer unit would mean a wiring inspection which would be the best option long term, for now would replacing the rest of the cartridge fuses be a sensible short term move?

Can you post a picture of the entire set up? as a lay person your post is a trifle hard to follow, no disrespect intended, but we can be a dumb bunch at times and a picture paints a better picture of what has been done. Or at least I can be a bit dumb at times, the others I'm not so sure.

 

[Paul Silver]

Can you post a picture of the entire set up? as a lay person your post is a trifle hard to follow, no disrespect intended, but we can be a dumb bunch at times and a picture paints a better picture of what has been done. Or at least I can be a bit dumb at times, the others I'm not so sure.

PDF attached!

 

[Paul Silver]

Replacing the cartridge fuses with mcbs will offer no better protection, and if the earth fault loop impedance of the circuits is too high then the mcbs may be worse than the cartridge fuses.
The mcbs will provide the convenience of being easier to reset after they have operated.

Thanks Dave, so might as well leave as is

 

[DPG]

PDF attached!

It may need approving by a moderator, with you being a new member and all that.

 

[Pete999]

PDF attached!

I see no pic Paul sorry

 

[Paul Silver]

Can you post a picture of the entire set up? as a lay person your post is a trifle hard to follow, no disrespect intended, but we can be a dumb bunch at times and a picture paints a better picture of what has been done. Or at least I can be a bit dumb at times, the others I'm not so sure.

Prob not clear enough, just made as my profile picture

 

[Paul Silver]

 

[Pete999]

Prob not clear enough, just made as my profile picture

Can't make it out Paul my eyes are not what they used to be.

 

[telectrix]

red wine goggles, pete?

 

[Octopus]

I would recommend you get a local spark through recommendation to come and take a look and advise...... ......... ......

 

[Pete999]

red wine goggles, pete?

Quite a possibility, you ceeky chunt

 

[telectrix]

that stand-alone RCD may have been added to your socket circuit. whatever, you need an electrician on site to sort that mess out.

 

[telectrix]

Quite a possibility, you ceeky chunt

touche.

 

[Pete999]

that stand-alone RCD may have been added to your socket circuit. whatever, you need an electrician on site to sort that mess out.

Agreed

 

[Paul Silver]

Here's a close up of the RCD. The white box is the heating (from the off peak F), and the grey fuse box the lights, sockets, etc. It's the 40amp RCD between the two that doesn't make sense to me...!

 

[Paul Silver]

Here's a close up of the RCD. The white box is the heating (from the off peak F), and the grey fuse box the lights, sockets, etc. It's the 40amp RCD between the two that doesn't make sense to me...! View attachment 37722

 

[telectrix]

it may not connect to the off peak CU, the cable could just pass through or behind. can't tell without the covers being taken off.

 

[westward10]

Does the rcd operate when you use the test button, if yes pull the fuses from the grey board until it does not to find the circuit it protects.

 

[Paul Silver]

it may not connect to the off peak CU, the cable could just pass through or behind. can't tell without the covers being taken off.

Thank you! It passes through it, for the bathroom fan heater. There's a fan heater in the kitchen, and a couple of panel heaters upstairs, all connected to the same circuit as the sockets. Assumed the bathroom heater was the same, but no, through this RCD.

 

[Paul Silver]

Does the rcd operate when you use the test button, if yes pull the fuses from the grey board until it does not to find the circuit it protects.

Thanks, found it's for the bathroom heater.

 

[Richard Burns]

Q1 has now been answered
Q2 yes an electrician should be able to disconnect this but may need a temporary disconnection from SSE (could be done at the time of the meter change if going to E7).
Q3 generally off peak F would be a good thing for storage heaters to boost the supply in the afternoon as in heavy use they often get cold, however if you find that they do not a boost in the afternoon then E7 may be OK, thought later owners may feel differently, but F is not really a current tariff any more. However if 25% is going to on peak then you are possibly on the borderline of effectiveness, difficult to say with being able to directly assess the loading on site. The change to a single meter would require the electrician to be there at the time they disconnect (for the best cost effectiveness)with an isolator ready to fit and henley blocks to split the supply installed ready to swap over when they change the meters.
Q4 has been answered.

 

[Paul Silver]

Q1 has now been answered
Q3 generally off peak F would be a good thing for storage heaters to boost the supply in the afternoon as in heavy use they often get cold, however if you find that they do not a boost in the afternoon then E7 may be OK, thought later owners may feel differently, but F is not really a current tariff any more. However if 25% is going to on peak then you are possibly on the borderline of effectiveness, difficult to say with being able to directly assess the loading on site. The change to a single meter would require the electrician to be there at the time they disconnect (for the best cost effectiveness)with an isolator ready to fit and henley blocks to split the supply installed ready to swap over when they change the meters.

Thank you Richard, that's very helpful. I've worked out that 22% of total use is standard energy, and 78% off peak F. Having the boost in the afternoon is good for the colder months.
If you look at 7 of the off peak hours transferred to economy 7 night rate, and the remaining 3.5 hours would be added the standard/off peak day rate, the usage shifts to 48% day & 52% night.
This would be a saving of up to £200 a year, but loosing the afternoon boost, so possibly increasing the need for an extra heater.
So this has led to the conclusion that it's probably best to stick with off peak f, and not change. Thank you

 

[Paul Silver]

Thank you all. Much appreciated to have all my questions answered.In summary:
Q1 - the RCD goes through (not to) the CU to feed 1 heater that was overlooked. My mistake!
Q2 The old TV supply is likely to need a temporary disconnection from SSE in order to be removed by an electrician.
Q3 Off peak F is probably better for storage heaters with the afternoon boost.
Because less than 25% is going to on peak (22% on peak, 78% off peak) then staying with off peak rather than changing economy 7 is likely to be best.
Econ. 7 may initially seem less expensive, but increase day use by loosing the boost may off set any cost benefit.
Q4 Replacing the cartridge fuses with mcbs will offer no better protection, and if the earth fault loop impedance of the circuits is too high then the mcbs may be worse than the cartridge fuses.
Thanks all

 

[Midwest]

Is it me or have I seen that picture before? Just remember the cobwebs and Henry hoover - no offence OP, have you posted before about this?

Otherwise, it's just a case of deja vu or I've started to early