Limiting current on a sub main

[JohnW2]

Do we know that? We've been told it's a "craft shop". For all we know the kettle might be used continuously for steaming something.

Possibly - although I would have expected bernard to have told us if it was something other than a 'normnal kettle', use for the normal purpose. As you will realise, I took 'kettle' to have its usual meaning - i.e. something used occasionally which, without bodging, will switch itself off as soon as its contents reach boiling point. If it is something other/more than that, perhaps bernard could tell us?

Kind Regards, John

 

[Iggifer]

I don't think it really matters if the kettle is boiling for 3 minutes or 3 hours, the fact is, to leave it with a 16a MCB and either not changing the set up / educating the users is a bad idea.

It could be that the MCB is a little trip happy, but changing it for another 16A is pointless, it's not solving the problem.

It could also be that they have 5A of halogen lighting, the items I mentioned plus the kettle and the heater, and the MCB is operating perfectly within spec.

 

[JohnW2]

It could also be that they have 5A of halogen lighting, the items I mentioned plus the kettle and the heater, and the MCB is operating perfectly within spec.

There's really too much speculation going on here. We need bernard to give us more precise details of the loads. However, I do agree that, even with just what we have been told about, a 16A OPD feeding everything is not really satisfactory.

Kind Regards, John

 

[EFLImpudence]

What's puzzling me is why Bernard is asking these things.

 

[JohnW2]

What's puzzling me is why Bernard is asking these things.

AIUI, all he was asking is whether it would be 'acceptable' (presumably in terms of BS7671) to have a 16A MCB feeding two other 16A MCBs within the same CU/enclosure.

However, as has been said, using an OPD to 'limit' the load to less than that load may sometimes be does not sound like an acceptable approach to me. The circuit, and that includes its OPD, should be designed to be adequate for 'foreseeable' loads.

Kind Regards, John

 

[Lectrician]

I've seen din rail modules that monitor current and switch of circuits when load exceeded. Used in caravans. Heaters turned off when sockets loaded. Can't find the details at the minute.

 

[JohnW2]

I've seen din rail modules that monitor current and switch of circuits when load exceeded. Used in caravans. Heaters turned off when sockets loaded. Can't find the details at the minute.

Yes, that is acceptable, but I don't think that using an OPD to 'limit' the load is.

Aren't French installations full of things like that, because of the way their electricity is sold (and 'limited')? - or did I dream that?

Kind Regards, John

 

[Lectrician]

Spain use MCBs in a sealed enclosure so you can reset but not get to terminals.

The device I've seen is fitted in caravans with heating to kill the heating in sections while socket loading is high.

 

[ban-all-sheds]

Aren't French installations full of things like that, because of the way their electricity is sold (and 'limited')? - or did I dream that?

No, I believe they are.

And with greater sophistication/granularity, and more centralised control, that's what the strategic aim of smart metering is.

 

[PBC_1966]

Aren't French installations full of things like that, because of the way their electricity is sold (and 'limited')? - or did I dream that?

No, you didn't dream it. I don't know if anything has changed more recently, but certainly when I was there last EDF based its standing charge on the supply capacity, and that charge increased quite rapidly with higher-rated supplies, hence people getting by with the smallest supply possible. I believe 3kW was the minimum offered.

 

[JohnW2]

Aren't French installations full of things like that, because of the way their electricity is sold (and 'limited')? - or did I dream that?

No, you didn't dream it. I don't know if anything has changed more recently, but certainly when I was there last EDF based its standing charge on the supply capacity, and that charge increased quite rapidly with higher-rated supplies, hence people getting by with the smallest supply possible. I believe 3kW was the minimum offered.

I realise that their are resource and infrastructure issues, with a lost of capital cost implications, but that nevertheless be a pretty unique business model. I think one would have to look very hard to find other large businesses that produced major disincentives to buy more of their product - it's a bit like "buy one, get a second for twice the price"!

Kind Regards, John

 

[Lectrician]

This is the consumer unit in my neighbours place in Spain. The MCB on the right is in a sealed box and is a C20 or 25, can't quite remember. There is no meter. You have to turn off A/C to cook the dinner etc.

 

[Spark123]

What is so wrong with the house supply that only a 16A supply is available?
A 16A supply to a shop is nothing, I can't even plug my yellow brick transformer into a B16A supply without it tripping the MCB.
I think the owner needs to cough up some cash and make it right (it does not comply with the regulations for discrimination for a start).

 

[JohnW2]

What is so wrong with the house supply that only a 16A supply is available?

I imagine that it's probably a standard house supply, the problem being that they're trying to run a shop off it, as well as the house.

Kind Regards, John

 

[Spark123]

I'm pretty sure if you applied diversity to it there will be a lot more capacity available than 16A tho, what is in the house that takes all the power?
Or is it a case of house owner doesn't want the business clocking up £££s on the electricity so only wants them to have a small supply?
If the supply is so piddly that there is no capacity left then a separate supply may be in order.