Diversity Calc Commercial Dishwasher 6.5kW single element

[Wilko]

Hi - if I understand correctly an intermittent load of 28A has been connected to a 13A plug. What happens to the 13A fuse? It sounds potentially dangerous to me.

 

[Ray Pooley]

Hi - if I understand correctly an intermittent load of 28A has been connected to a 13A plug. What happens to the 13A fuse? It sounds potentially dangerous to me.

This is in fact the actual gist. It should blow at 1.66 times the rate which is about 21 amps. But it doesn't. Why doesn't it if it gets to 28A? I wouldn't mind sticking a clamp meter on it to see what the actual draw is just out of curiosity but I can't really. If you look at te theory it shouldn't work. But it does and without any noticable issues. For the last three years.

 

[DefyG]

Not verbatum. So. C1, C2 or C3 then. If you had to.

I wouldn't on someone else's word.
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If you look at te theory it shouldn't work. But it does and without any noticable issues. For the last three years.

And we've all come across similar instances where showers have been connected to a 2.5 t&e straight off a 32A RFC.

It works but it doesn't make right or correct!

Not sure what the real issue is here, why were you looking at the DW in the first place, if 'Its been working ok for the last 3 years', why or just curious?

 

[westward10]

I find it highly unlikely this appliance for the last three years has been connected for 6.5kw through a 13A plug and never had an issue. From this link it indicates it can be connected for different power ratings however for 13A the flex will require changing.

Maidaid Amika 50XL-D Undercounter dishwasher - 18 plate -

Maidaid Amika 50XL-D Undercounter dishwasher - 18 plate . 20+ years experience. Free delivery, expert advice & service

www.chefsrange.co.uk

 

[snowhead]

As above, there's no way it's survived with 6.5kw on a 13amp plug.
It's most likely been converted from 6.5kw heater to 2.1kw heater by the supplier, either from new or as used.

 

[DefyG]

It's most likely been converted from 6.5kw heater to 2.1kw heater by the supplier, either from new or as used.

So not a fixed 6.5kW load as per original OP, but one that can be terminated probably for 1ph 2.1kW element, which would account for it being ok (Not tripping or any thermal damage) on a 13A plug/socket.
And at 6.5kW could be 3ph??

 

[Ray Pooley]

Built and delivered from warehouse as stock 25/09/2017. 4.0mm² 3 core black flex.
Three years old. New to the customer. That's the way it is. I don't have a picture of the plug ans socket. I'll take one tomorrow. The problem it has is a faulty main boiler thermostat. This is the first issue it has had since new.
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An interesting experiment by John Ward. The destruction of a power cable. The point to note in this video is that the plug is a 13A plug and fuse. These continue to serve current up to 23.4 VAC.
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And here's teh video.

View: https://www.youtube.com/watch?v=rfU5lzXAHAQ&t=61s&ab_channel=JohnWard

 

[DefyG]

Why would anyone put it on a 13A plug when the nameplate clearly states 30A?
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Not sure what your point is with the video ............ Its still doesn't qualify for diversity and is currently incorrectly terminated .... 'in my book'!

 

[snowhead]

I'm not sure why this thread has run to 23 posts.
As above a 13amp plug and socket is not suitable for a 6.5kw load, if that's what it really is.
Diversity doesn't come in to it.
It needs a suitable plug / socket or connection and a suitable supply to it, if the existing one is not.

 

[davesparks]

The data plate clearly states that it has a power consumption of 6.5kW and requires a 30A supply so that is what it should be connected to. If they want it on a plug then a 32A plug would be appropriate.

Diversity cannot be applied to the supply to the appliance if it is a single heating element as that element will only be either on or off, appliances with multiple heating elements controlled by different thermostats can have diversity applied as they will all be cycling on and off at different times.

Diversity can be applied when considering the supply to the DB that then feeds this machine (assuming it is fed from a DB which feeds multiple circuits) but this does not have any bearing on the supply to the machine itself.

As to how the plug has not burned out yet, it is probably probably luck or an incorrect fuse or a modified appliance......

 

[pc1966]

At 30A a genuine 13A fuse would below somewhere between 1s and 40s, so it seems very unlikely it really is that sort of a load.

 

[DPG]

You say it has 4mm flex fitted. Can you show a picture of the 13A plug to show how it has been fitted.

 

[Jim_e_Jib]

In the link that Westward provided in #19, it says:

Machine will be set for 30amp supply with relevent cable, if they are ordered for 2.6kw 13 amp supply, the cable will need to be changed by the installation engineer as a UK 3 pin plug will not fit onto the cable

Has it been supplied as the 2.6KW unit and the installation engineer just butchered a 13amp plug on the supplied cable rather than replacing it?

 

[Vortigern]

Hope it's got a PAT test cert.

 

[DPG]

In the link that Westward provided in #19, it says:

Machine will be set for 30amp supply with relevent cable, if they are ordered for 2.6kw 13 amp supply, the cable will need to be changed by the installation engineer as a UK 3 pin plug will not fit onto the cable

Has it been supplied as the 2.6KW unit and the installation engineer just butchered a 13amp plug on the supplied cable rather than replacing it?

Yes, It sounds like they're put a 13A plug on 4mm flex to me!