Current Oven Wire

[PrenticeBoyofDerry]

I thought I had, but I've just looked at the Stoves website and they don't seem to do freestanding ovens - only built-in ovens or freestanding cookers! So I think we're back to needing to know the make/model from the OP!

As you say they do do a selection of free-standing cookers.

http://www.stoves.co.uk/products/cooking/freestanding-cookers/

The OP must be purchasing a cooker, I did ask for spec but not yet had reply from OP!

"Stoves" do a dual fuel cooker, one which is rated at 4.1kW-4.9kW, 220V/240V, the MI does however state that 6mm2 flex should be used to connect.

 

[JohnW2]

4.9kWh

Yes, we have all assumed that it was a typo for 4.9kW. Maybe we're all wrong.

As I've said. we need the make (assumed "Stoves") and model from the OP.

Kind Regards, John

 

[JohnW2]

As you say they do do a selection of free-standing cookers. ... The OP must be purchasing a cooker, I did ask for spec but not yet had reply from OP!

Indeed you did - as did I (more than once). We obviously need that information.

"Stoves" do a dual fuel cooker, one which is rated at 4.1kW-4.9kW, 220V/240V, the MI does however state that 6mm2 flex should be used to connect.

They obviously have not heard of, or do not believe in, diversity. As I wrote earlier, 4.9kW at 240V is just under 13A at 230V with diversity. In theory, 1.25mm² flex would be adequate for that!

Kind Regards, John

 

[ban-all-sheds]

4.9kWh

Yes, we have all assumed that it was a typo for 4.9kW. Maybe we're all wrong.

Given how (in general) it is both

a) easy to find kWh ratings for cookers
b) hard to find actual loads

I was assuming that the OP was quoting a kWh figure.

 

[JohnW2]

4.9kWh

Yes, we have all assumed that it was a typo for 4.9kW. Maybe we're all wrong.

Given how (in general) it is both a) easy to find kWh ratings for cookers ... b) hard to find actual loads ... I was assuming that the OP was quoting a kWh figure.

Yes, you may be right. However, as PBoD has said, Stoves do do a dual-fuel cooker with an oven which is 4.9kW at 240V, so I think my money is probably on something like that.

We need the OP to identify this appliance.

Kind Regards, John

 

[winston1]

Often when one finds 2.5mm it is a fused or unfused spur from a larger circuit often the ring final. With the latter even a 3kW fixed appliance should not be connected.

Why?

 

[flyingsparks]

Often when one finds 2.5mm it is a fused or unfused spur from a larger circuit often the ring final. With the latter even a 3kW fixed appliance should not be connected.

Why?

Max recommended fixed load on a ring is 2kW.

 

[winston1]

Often when one finds 2.5mm it is a fused or unfused spur from a larger circuit often the ring final. With the latter even a 3kW fixed appliance should not be connected.

Why?

Max recommended fixed load on a ring is 2kW.

Ah, so not regulation then.

Now ericmark tells us washing machines, dryers etc are considered fixed appliances, so can't be plugged in to a ring final, yet all these appliances are sold with fitted 13amp plugs.

Joe public will be well confused, not to mention annoyed when told he can't plug his new appliance in.

 

[RF Lighting]

We've told you more than enough times why heavy fixed loads should be kept off ring circuits, and why the IET recommends this.

It's clear that none of this has sunk in to your thick skull.

Please don't come to this forum and dish out your normally incorrect advice, and encourage bad practice.

 

[winston1]

That does not answer the question. It is NOT a regulation and so called fixed loads come fitted with 13a plugs. Why? A ring final can carry 7kW after all.

 

[JohnW2]

A ring final can carry 7kW after all.

Only if that 7kW is distributed appropriately. 7kW's worth of load connected close to one end of a ring final could overload the short arm of the ring cable (which may have a CCC of only 20A).

Kind Regards, John

 

[bernardgreen]

That does not answer the question. It is NOT a regulation and so called fixed loads come fitted with 13a plugs. Why? A ring final can carry 7kW after all.

Goto http://www.tlc-direct.co.uk/Technical/Charts/VoltageDrop.html and enter 7kW as the load over 1 metre

The result is that 6 mm² of copper is required to carry the current.

Put that load at the midpoint of a ring final. With equal current in each leg then each leg will require 3 mm² of copper which is more than 2.5 mm²

If the load is close to the ends of a ring then the current in the shorter leg will be more than half the current.

That is why heavy loads should not be connected to a ring final constructed with 2.5mm² copper cable.

 

[RF Lighting]

We've been through this so many times with Winston. He's just too stupid or to obstinate to accept any explanation as to why it's a bad idea to hang heavy loads off a ring.

It's time we stopped entertaining this clown.

 

[JohnW2]

That does not answer the question. It is NOT a regulation and so called fixed loads come fitted with 13a plugs. Why? A ring final can carry 7kW after all.

Goto http://www.tlc-direct.co.uk/Technical/Charts/VoltageDrop.html and enter 7kW as the load over 1 metre ... The result is that 6 mm² of copper is required to carry the current. Put that load at the midpoint of a ring final. With equal current in each leg then each leg will require 3 mm² of copper which is more than 2.5 mm²

Yes, if you use TLC's default Method 100 installation (which more-or-less corresponds to the 20A minimum CCC allowed in a ring final). If you changed it to Method C, it would say 4mm², half of which is 2mm².

However, the calculator is misleading. 7kW is about 30.4A at 230V, so if it's all at the middle of the ring, the current in each arm will be about 15.2A - which, theoretically (although not allowed) would be OK with 1.5mm ² cable, let alone the 3mm² you suggest. There is absolutely no problem with a 2.5mm² ring circuit if the load is all at the middle, or reasonably evenly distributed around the ring. The problem arise with other load distributions ....

If the load is close to the ends of a ring then the current in the shorter leg will be more than half the current.

As I recently wrote, that's the problem. 7kW (30.4A at 230V) connected, say, 10% of the way along ring would result in about 27.3A in one arm of the ring and 3.1A along the other arm - the former being much too much if the cable had the minimum permitted CCC (for a ring final) of 20A.

Having said all that, if (as will commonly be the case) the ring cables installation is Method C (27A CCC for 2.5mm²), it is all-but impossible to overload the cable, even if the entire 32A load is applied close to one end - to make overload actually impossible, all one has to do is ensure that there are no sockets within the first (or last) ~10% of the ring run. In fact, just one double socket, and even if it were loaded to 26A, close to one end would not be enough to enable an overload to arise.

Kind Regards, John

 

[JohnW2]

We've been through this so many times with Winston. He's just too stupid or to obstinate to accept any explanation as to why it's a bad idea to hang heavy loads off a ring. t's time we stopped entertaining this clown.

Whilst I would agree that many of the bees in winston's bonnet are just plain irritating, on this occasion I have some sympathy, since I think that the problems of "hanging heavy loads off a ring" are probably overplayed. As I've just written, certainly if the cable is clipped direct, one can design a ring that cannot be overloaded, no matter what loads are connected where. ... and we know that there are countless 'heavy loads' plugged into ring finals

I wonder if anyone has actually seen a case in which the cable of a (properly designed and installed) ring final has suffered, let alone caused any 'catastrophe', as a result of the loading?

Kind Regards, John