Use of the 45amp circuit

[alanrco]

I don't use the high power circuit (45amp) in my home for cooker or shower etc. You may think this is a daft question, but better safe than sorry. Can I use this circuit safely for normal use I.e. I'm running a cable through a wall to my living room to place a 2 gang socket for my tv system. There is no socket in that location and this would be the most convenient solution as well as hide an unsightly cable? I understand that a correct fuse is needed for the tv etc.

Thanks,

Alan

 

[Technician]

If the current device is a re-wirable fuse I suggest you change that

for a small circuit breaker to suit your socket circuit. You could get

away with a 16A BS60898 device and all you do is remove the fuse

carrier and replace it with the carrier for the circuit breaker.

You will need to wire the circuit in 2.5mm and this would normally

require an installation certificate because you are adding a new circuit

onto an installation which, up to now, has not been used.

Because of the EIC, notification to Local Authority Building Control will

be required, but there are a lot of very good guys on here who may

be able to give you a short cut.

I have given you the absolute long hand way of doing it but as I say,

others may be able to give you the short hand advice. Someone on

this forum may be local to you to give you a hand.

HTH

 

[alanrco]

If the current device is a re-wirable fuse I suggest you change thatfor a small circuit breaker to suit your socket circuit. You could get

away with a 16A BS60898 device and all you do is remove the fuse

carrier and replace it with the carrier for the circuit breaker.

You will need to wire the circuit in 2.5mm and this would normally

require an installation certificate because you are adding a new circuit

onto an installation which, up to now, has not been used.

Because of the EIC, notification to Local Authority Building Control will

be required, but there are a lot of very good guys on here who may

be able to give you a short cut.

I have given you the absolute long hand way of doing it but as I say,

others may be able to give you the short hand advice. Someone on

this forum may be local to you to give you a hand.

HTH

Thank you for such a prompt reply!

Alan

 

[ProDave]

There's the small matter of a new circuit usually requires RCD protection, and I'll bet your fuse box does not have an RCD.

Simplest solution is a stand alone RCD in a box next to the fuse box.

Can you clarify, are you running a new cable all the way from the new socket to the fuse box, or are you using the existing (probably 6mm or 10mm) cable?

More information needed. But whatever you do, you will need to change the 45A fuse for something lower, and preferably an MCB rather than a fuse.

 

[S60TEM]

If you are simply wanting to use the existing 6mm or probably 10mm (as it is on a 45A cpd) circuit to convert to a socket outlet then yes you can do this although you will find it hard to terminate 6mm into a socket let alone 10mm!! The fuse or circuit breaker is there purely to protect the cable, not the appliances that are plugged into it as they are protected via their plugtop 3, 5 or 13A fuses. As said above though, I would probably reduce the mcb down to at least a 20A and you then need to think about RCD protection as if it is a pre 17th edition split load board then you might find as it was a circuit greater than 32A and for a cooker then it may not be RCD protected for use by unskilled persons. Either way, I think it would be best you have it checked and tested to verify that the earth loop impedance is low enough to trip the MCB or fuse within the required time.

 

[a1]

From reading the OP guys, it is my belief that OP doesn't want to do a straight swap of the Cooker switch to a double Switched/Unswitched Socket Outlet, but rather, come off of it, through his wall, to add a dsso the other side of the wall for his tv.

 

[SLIPSHOD & SLAPDASH]

If the current device is a re-wirable fuse I suggest you change thatfor a small circuit breaker to suit your socket circuit. You could get

away with a 16A BS60898 device and all you do is remove the fuse

carrier and replace it with the carrier for the circuit breaker.

You will need to wire the circuit in 2.5mm and this would normally

require an installation certificate because you are adding a new circuit

onto an installation which, up to now, has not been used.

Because of the EIC, notification to Local Authority Building Control will

be required, but there are a lot of very good guys on here who may

be able to give you a short cut.

I have given you the absolute long hand way of doing it but as I say,

others may be able to give you the short hand advice. Someone on

this forum may be local to you to give you a hand.

HTH

I have never ever seen 45A fuse wire, if it does exist its as rare as a John Harrison H6 Lesser Watch.

 

[ProDave]

I have never ever seen 45A fuse wire, if it does exist its as rare as a John Harrison H6 Lesser Watch.

Almost certainly a cartridge fuse, or plug in MCB.

Still waiting for the OP to clarify exactly what he wants to do. How much of the old circuit will be used? how much new wiring will be used? How will he join the old to the new? is the 45A circuit currently in use, or was it disconnected some time ago?

 

[lineman]

At no point has the op mentioned that his cu is either rewireable or plug in mcbs.

 

[Sidewinder]

I can't see how it can be fuse wire IIRC fuse wire went from 30A to 60A, i.e. no 45A!

---------- Post Auto-Merged at 20:16 ---------- Previous post was made at 20:14 ----------

Same as the plug in mcb, can't recall a standard Wylex 45A 3871 or 60898 plug in.

There never would have been a 45A 3871 IIRC, I'd have to check an old regs book though.

 

[Manator]

It is a very good question, however more information is required, as prodave says.

Firstly is this circuit comming off the cable, or from the distribution/fuse board?

The wall you are going through is it behind the fuse board, or the end of the 45 amp circuit?

What size cable is fitted if any?

What size cable do you propose to use?

Can the cable can be installed in metal conduit to the TV?

Remember that TV circuits do not draw that much power, and the normal fuse rating in the plug tops for TV's is only 5 amp.

 

[OnOff]

Seem to be a few 45A 3871s on eBay:

WYLEX BS 3871 B45 MCB 45 Amp M2 Plug Push ## USED ## | eBay

 

[Sidewinder]

Apologies, I could not remember a 45A 3871 & my memory told me that this was not a standard capacity under 3871, originally.

As I said though I would have to check really, perhaps these are not from the original 3871 standard, but the later one, the only copy I have is from 1981 which also mentions B, C & D types, it is down to number series and for the life of me I can't remember what was in place when I was that young!

 

[SLIPSHOD & SLAPDASH]

Almost certainly a cartridge fuse, or plug in MCB.

 

[a1]

Have I mised something here? Why is everyone assuming that it is a re-wirable fuse?

 

[SLIPSHOD & SLAPDASH]

Have I mised something here? Why is everyone assuming that it is a re-wirable fuse?

Only people that dont know much.

 

[Doc Hudson]

Wylex HRC Fuse Carriers & Fuses

As suggested earlier HRC cartridge is possible, but I still think the 45A were quite rare as the higher power appliances were not that common in domestic installations and many Wylex main switches were max 60A or 80A.

Doc H.

 

[Technician]

I do admit to omitting the RCD in my post.

It should have been there.

However, the OP stated that it was a 45 Amp

for a cooker/shower and I ASSUMED it was a BS3036

fuse carrier.

There is nothing wrong with changing the

fuse carrier for a C/B holder like a wylex if

the original fuseholder is the same make.

I have seen this done, following tests to verify

suitability.

Slipshod's reference to the John Harrison watch was

probably timely.

---------- Post Auto-Merged at 14:09 ---------- Previous post was made at 13:13 ----------

Here it is; BS3036 45 Amp.

Page 56 of the regs.table 41.4

allowable Zs 1.59 ohm (uncorrected)