Ovens on cooker ccts

Perhaps a  look through this Chris?!!!

https://shop.theiet.org/code-of-practice-for-in-service-inspection-and-testing-ofelectrical-equipment-4th-edition


Regards


BOD

4th Edition, p20, under Scope 1.2:

portable appliances or equipment

movable appliances or equipment

stationary appliances or equipment

hand-held appliances or equipment

built-in appliances or equipment (generally domestic or similar) What's portable about an appliance which is fixed to the building's structure? ?

IT equipment

extension leads, RCD extension leads, multiway adaptors, RCD adaptors

equipment with high protective conductor currents

surge protective devices (SPDs).


Regards


BOD

To state the obvious, you can insulation test a built in oven from the consumer unit and test earth continuity with a wander lead, again from the MET in the consumer unit.


So at most you only need to slide it forward for a quick look behind it.


Andy Betteridge

Several gas gas fitters have told me that they are not supposed to refit a previously installed gas cooking appliances if the customer does not have the original installation instructions that came with it.


So would you code an electric cooker as FI and declare the  entire installation is unsatisfactory, because the cooker installation instructions are not available for you to check what type of cable the manufacturer said to use to connect it?


Andy B.

Gas fitters are an incredibly conservative bunch, and I am not convinced that overdoing that approach makes things any safer, beyond a certain point it just becomes obstructive. Most gas accidents are really inhalation of  fumes from imperfect combustion, not the building wrecking explosions beloved of the film makers.


It is quite fun to look at  gas accident stats from the pre-corgi (1990) era up to about 2000  


Much like electrical accidents pre-and post part P the anticipated reduction in accidents is modest from say 1987 to 2000, and quite a lot of that may have happened anyway, as the figures were already on a falling trend as things like room vented water heaters were falling out of use, and older converted town gas era equipment  generally being retired. It is hard to know since then how much is change in reporting standards, and product standards for new appliances.

We do not have a parallel universe to compare with of course, but it is worth bearing in mind that the improvement is not so great.


Back to the OP.

Here is one slightly extreme view.


If the oven on its thin flex is on the cooker circuit, so the MCB is 32 or 40A instead of a 15A fuse or whatever, how much more dangerous is it ?

Firstly not dangerous at all until there is a fault. Then only if there is a fault that is not contained within the oven. It may be more expensive to repair if the internal wiring has served in place of the makers suggested fuse, but unless the outer touchable parts remain live afterwards, or the case fails as a containment, and flames and molten metal are jetted across the kitchen, you may say "so what? - it needed a repair anyway" - or more likely nowadays replacement, regardless of fault complexity.

If earthing is not going to melt before the live core, and R2 is OK to fire the breaker promptly, then the only remaining question is the containment of the shrapnel aspect (!).

It takes a lot more than the let-through energy of a B32 breaker,  to cut even a spot hole in steel plate,  you'd probably still  struggle with a 100A company fuse  as the only limiting element, so I'm not really finding that credible either.


So, not nice perhaps, but scarcely a high risk


(Later in another cooker related post I'll be explaining why it is not OK to demonstrate burning magnesium to your kids on the gas ring while your wife is out, if there is any risk of her coming back for her purse before the smoke clears, or to drain the petrol tank of a generator over the hall and landing carpet, even by mistake.)

How is pulling out an oven, which requires a degree of dismantling; or lifting a hob; or indeed pulling out any other item of fitted kitchen appliances, consistent with GN3 para 3.8.1 Scope: "... The inspection is carried out without taking apart or dismantling equipment as far as possible."?