EICR Coding for hob wiring

[ray-bentos]

I did an EICR on a property today and came across a built in hob with a 45A switch but no dedicated cooker circuit

On further inspection it turns out that the 45A switch is spurred from the kitchen socket ring and feeds a double socket at the back of the built in oven. Both the oven and the hob are wired with 13A plugs. This is obviously fine for the oven but the hob is rated at 5.7KW.

From a safety point of view I suppose it is not 'unsafe' as if it were to draw more current than the plug allowed it would simply blow the fuse but its a bit of a bodge for me. The tenant reports it working fine so I can only guess that it never reaches anything like 5.7KW as that would need all 4 hobs on full power.

How would you be inclined to code this on an EICR? I don't see it poses either an immediate danger or a danger under fault conditions due to the 13A fuse in the plug, therefore can only code C3 but what reg would you point to?

I'm tempted to cite 433.1 "every circuit shall be designed so that a small overload of long duration is unlikely to occur" however this applies to circuits themselves so can this be used in this instance?

 

[Octopus]

Did the hob come fitted with a 13A socket? Some do!

 

[telectrix]

agree. 433.1.103 and a code C3, possibly a code C2 as i've seen plug/sockets melted without the 13A fuse blowing.

 

[ray-bentos]

Did the hob come fitted with a 13A socket? Some do!

from what I can tell no, it has wiring diagram on the back the same as cooker/hob to be hard wired.
Also the cable used is identical to that on the built in oven leading me to believe its perhaps been done by a kitchen fitter.
The building is all wired in old red/black but the 45A switch and 2G socket underneath are in harmonised cable so look like they were done as part of kitchen fit out perhaps?

 

[Octopus]

agree. 433.1.103 and a code C3, possibly a code C2 as i've seen plug/sockets melted without the 13A fuse blowing.

On what basis?

 

[Octopus]

from what I can tell no, it has wiring diagram on the back the same as cooker/hob to be hard wired.
Also the cable used is identical to that on the built in oven leading me to believe its perhaps been done by a kitchen fitter.
The building is all wired in old red/black but the 45A switch and 2G socket underneath are in harmonised cable so look like they were done as part of kitchen fit out perhaps?

I'd check the manufacturers instructions...

 

[ray-bentos]

I'll have to check online for a copy but is it standard practice to provide a 13A plug for something which could potentially draw 23A according to the rating plate?

I'm not arguing either way just interested to know as it seems pretty slack by the manufacturers to do this.

In the event the manual states it should be hard wired in, where does that leave me with regards coding? Again does it pose either an immediate danger or a danger under fault conditions?

 

[telectrix]

On what basis?

code C3 if there was no perceived potential danger. reading from app15. p425 bgb. fig. 15A which refers to 433.1.103

 

[Octopus]

code C3 if there was no perceived potential danger. reading from app15. p425 bgb. fig. 15A which refers to 433.1.103

But if both hob and oven are supplied with 13A plugs from the factory there would be no code, nothing........ IMHO

 

[ray-bentos]

Quick search brought the manual up, Whirlpool AKT 809/NE

Turns out it doesn't come with a 13A plug and requires 4mm cable so fails on both the connection method and the thickness of the cable supplying the unit.

So does this now pose a C2 risk as the cable is undersized or does the 13A fuse mitigate the overload risk and just bring us into C3 territory?

 

[davesparks]

What did you calculate the current of the job to be?

 

[ray-bentos]

What did you calculate the current of the job to be?

I assume you meant hob?

Rating plate states 5.7KW

5700/230 = 24.78A

even working at a more realistic:

5700/240 = 23.75A

 

[infinity]

Diversity?

 

[Silly Sausage]

Quick search brought the manual up, Whirlpool AKT 809/NE

Turns out it doesn't come with a 13A plug and requires 4mm cable so fails on both the connection method and the thickness of the cable supplying the unit.

So does this now pose a C2 risk as the cable is undersized or does the 13A fuse mitigate the overload risk and just bring us into C3 territory?

Yes, :iagree:

 

[Octopus]

Quick search brought the manual up, Whirlpool AKT 809/NE

Turns out it doesn't come with a 13A plug and requires 4mm cable so fails on both the connection method and the thickness of the cable supplying the unit.

So does this now pose a C2 risk as the cable is undersized or does the 13A fuse mitigate the overload risk and just bring us into C3 territory?

Good hard facts to add to your EICR.

Like it.

I'm half way through a kitchen refit where the induction hob has come with a 13A plug fitted. That said I'm connecting it to the "previous" hob radial but using a socket below the worktop rather than an outlet plate!

 

[davesparks]

I assume you meant hob?

Rating plate states 5.7KW

5700/230 = 24.78A

even working at a more realistic:

5700/240 = 23.75A

As I suspected you haven't calculated the load correctly, you should be taking the first 10A of FLC plus 30% of the remainder.

Which gives the load as 14.1A rather than your 23.8A which makes it a small overload as per the regulation posted above, the 23.8A is not a small overload as it is nearly a 100% overload.
Now you just have to decide whether that is a sustained small overload or a short duration small overload.
If it is sustained I would say it is potentially dangerous.
If it is short duration then no problem.

Are you sure you should be carrying out EICRs if you don't know how to apply basic diversity calculations?

 

[Charlie_]

I assume you meant hob?

Rating plate states 5.7KW

5700/230 = 24.78A

even working at a more realistic:

5700/240 = 23.75A

At 240v the current would be greater than it would at 230v

 

[Charlie_]

Diversity?

They won Britain's Got Talent a few years ago

 

[tigerpaul]

At 240v the current would be greater than it would at 230v

No the current is greater at 230 than at 240

 

[SJD]

No the current is greater at 230 than at 240

Umm, the load is fixed, and it will be spec'd to be 5.7kW at either 240V or 230V.
Often the load is spec'd at 240V if the manufacturer wants it to sound bigger.