New Cable needed??

Bobbya82 · 13 Sep 2006

Hi,

I am going to replace my electric oven soon, at the moment it is a very old all in one cooker and will be replaced with an integrated hob and oven. Obviously I wont be doing the electrics myself but just so I can be pre warned, will I need new cable installed to supply the new oven. At the moment I have the dedicated 45A socket but am unsure if the old cable will be sufficient

Hope this is clear, let us know if you need more details.

Thanks in advance.

didthathurt · 13 Sep 2006

I am assuming you have a 45A Cooker control unit with an integral socket and a connection unit behind the cooker into which the cooker is hard wired. The answer to your q re the cable depends upon what you have, cable wise, and what you are intending to install. I would hope you have a cable that is at least a 6sq mm Twin and Earth cable, as this is the absolute minimum for a 45A load and will cope with all but the largest and most powerful cooking equipment. If a change is decided upon, I generally recommend 10sq mm cable as, tho it is a little bit of overkill, it makes any future upgrading of the circuit easier.

Bobbya82 · 13 Sep 2006

Yep it is a dedicated cable with socket cabled into the cooker. The new oven is nothing fancy just a Wickes Moffat ceramic hob and double oven. The cable is alot thicker than normal I assume the 6MM you mentioned. Its just that it is probably the original cable from when the flat was built, the Fuse box or whatever its called now days is the old style plugin fuses. AM I right in thinking though that if it was ok with the old oven it should be fine with the new?

thanks for your help.

didthathurt · 13 Sep 2006

Yes, unless there is a large disparity in the rating of the old and new, which I would doubt from what you say, or the wiring needs replacing, anyway, purely due to its age.

JohnD · 13 Sep 2006

If you have plugin fuses your old fusebox might be limited to max 30Amps per circuit.

Is it a Wylex?

Is it Brown?

Is there a legend or sticker by the main switch saying "Total load not to exceed 60 Amps?"

Is there a row of fuses all together, and one separate, rather big fuse, all on its own?

Bobbya82 · 14 Sep 2006

John,

Thanks for you reply,

Dont know if it is a Wylex, will need to check tonight.

It is not Brown but grey.

Also need to check sticker

All the fuses are the same size, There is a 45A for the cooker, 5A for lights and 15A for plugs. ( That is roughly what I think it says)

Does that help?

Thanks.

JohnD · 14 Sep 2006

(edited - a smaller one - (top left!) )

Grey metal?

Like this

(edited - for the info of anyone wondering... the transparent acrylic cover over the MCBs is in fact a Wilkinsons plastic Sandwich box, with the rim trimmed to clip into the sides of the metal enclosure

It stops anything brushing against the push-button MCBs and tripping them!

((not my house!))

Bobbya82 · 14 Sep 2006

John,

Yes Grey, yes smaller and sort of simular. I will get all the details tonight and post again. But are you saying that if it is simular to the picture it wont be up to the job?

Thanks.

JohnD · 14 Sep 2006

Maybe... maybe not. Some of the later metalclads like I showed have a 100A main switch (I have changed the pic, BTW - the 12-way is a lot bigger and has the central switch, most have a switch at the RH side)

Bobbya82 · 14 Sep 2006

That more like the one I have, will take a pic tonight and post in the morning.

Thanks for your help on this.

didthathurt · 14 Sep 2006

pcharles said:
All the fuses are the same size, There is a 45A for the cooker, 5A for lights and 15A for plugs.

I appreciate what JohnD is saying, but think it's what we used to call a "Leafy Lane". Nice to walk down but not actually dealing with the point in question. The point here is that you are not proposing to add to the installation, nor upgrade the supply or anything other than put a different cooker in. As I said, earlier, unless there is a large disparity between the ratings of the old and new i.e. the new is drawing a significantly higher current, you're not really changing the situation at all and if it's worked like this safely for the past goodness knows how long it will continue to do so until age takes its natural toll. So, I still consider the answer to your question to be no, you will not need to upgrade your wiring or CU purely to cope with a new cooker subject only to the disparity proviso above.

Bobbya82 · 14 Sep 2006

Just reading the manual for hob, apparently I need a H05VV-F cable, assume that is pretty standard and this is what the old oven is using.

didthathurt · 14 Sep 2006

pcharles said:
Just reading the manual for hob, apparently I need a H05VV-F cable, assume that is pretty standard and this is what the old oven is using.

This is H05VV-F flex.
http://elandcables-specs.co.uk:8080/eland/details?CableTypeID=106
used between the Connection Unit and the cooker itself as opposed to that from the CU to the Cooker Unit. I'm not sure if it comes in a size above 4sq mm, which suggests your cooker should be on a 32A MCB not the 45A one it's on now (this would support a cooker rating of up to about 15.5kW - deapplying diversity - assuming you have an integral socket in the control unit).

Bobbya82 · 15 Sep 2006

Thanks,

From what has been said the new oven should not cause any problems.

In reply to JohnD, yes the box was a WYLEX, Has cat no 606 on it and load not to exceed 63AMPS.

Thanks again.

securespark · 15 Sep 2006

didthathurt said:
pcharles said:

All the fuses are the same size, There is a 45A for the cooker, 5A for lights and 15A for plugs.

Click to expand...

I appreciate what JohnD is saying, but think it's what we used to call a "Leafy Lane". Nice to walk down but not actually dealing with the point in question. The point here is that you are not proposing to add to the installation, nor upgrade the supply or anything other than put a different cooker in. As I said, earlier, unless there is a large disparity between the ratings of the old and new i.e. the new is drawing a significantly higher current, you're not really changing the situation at all and if it's worked like this safely for the past goodness knows how long it will continue to do so until age takes its natural toll. So, I still consider the answer to your question to be no, you will not need to upgrade your wiring or CU purely to cope with a new cooker subject only to the disparity proviso above.

Didthathurt

I feel JohnD has a valid point to make: Wylex boards with a sub-100A switch were never designed to accept any device greater than 32A, hence the tab on the rear of the 35/40/45A fuse-shields. To brush away his concerns as a "leafy lane" is irresponsible IMO.

You are saying that the OP is not proposing to add to the existing install. What I am saying categorically is that it has been already added to beyond its design, and that is wrong. Just because it works and has been that way many years does not mean it is safe.

The fact is that the cooker circuit is placing a higher load on the CU than it was designed for, and this needs rectifying.

Not only that, but if the CU is inadequate, the likelihood is that tails are undersized, too. A load in excess of 63A load is not unfeasible in this situation, if the cooker is in full use.

Speak to technical at Wylex (0161 998 5454) for confirmation of this.

diynot

If you need to find a tradesperson to get your job done, please try our local search below, or if you are doing it yourself you can find suppliers local to you.

Select the supplier or trade you require, enter your location to begin your search.

Are you a trade or supplier? You can create your listing free at DIYnot Local

New Cable needed??

Similar threads