Limiting current on a sub main

[bernardgreen]

The original idea was that the shop ( which is very small ) would have an un-metered electricity supply included in the rent. So fit a low amperage MCB in the sub main to restrict the maximum load to an agreed value. But after the first year it was realised that heating over the winter had used a lot of electricity and probably the rent wouldn't cover it next winter. Hence a meter was fitted and electricity to the shop is now paid for separately to the rent.

It has just been discovered that the MCB supplying the shop is a B32 and not 16 amps as first though so what were the staff in the shop using to trip that ?.

 

[JohnW2]

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?

In terms of diversity over a reasonable period of time, you're undoubtedly right. In the short-term, many/most households are obviously capable of using at least the full amount of the theoretical supply capacity (e.g. shower+oven+hob+something else).

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?

Possibly. That question has been asked a couple of times. We don't even know whether the house owner also owns the shop/business.

Kind Regards, John

 

[PBC_1966]

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 was always led to believe that at least in the past, EDF really did have problems with heavy loads due to its infrastructure, hence the tariff structure to try and discourage people from making higher demands during peak load times. I just found the current rates for the base tariff:

https://particulier.edf.fr/fr/accue...ervices/les-offres-d-energie/electricite.html

And with apologies to Bernard for going further off topic:

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"!

PG&E (Pacific Gas & Electric) out here actually operates a tiered system intended to discourage "excessive" use by increasing the rate per unit once you go over certain limits each month:

http://pge.com/en/myhome/saveenergymoney/plans/tiers/index.page

The actual allocation of units in the different tiers varies depending upon location within the state and whether or not you have electric heat as your primary heat source.

Here in Redding it's much simpler, as the city operates its own electric utility and we pay a fixed rate per unit no matter how much is used each month.

 

[JohnW2]

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 was always led to believe that at least in the past, EDF really did have problems with heavy loads due to its infrastructure, hence the tariff structure to try and discourage people from making higher demands during peak load times. I just found the current rates for the base tariff: ...

Fair enough. However, AFAIAA, that situation has existed for decades. If they had wanted to grow their business and hence increase profits, one would have expected them to have invested in improving the infrastructure - so that, just like almost every other company who sells things, they could then have spent their time encouraging, rather than discouraging, customers to buy more of their product! Is EDF entirely state-owned? If there were 'public shareholders', I might have expected them to moan about policies designed to restrict the sales, hence profits! ... and I'd say the same about PG&E!

Kind Regards, John

 

[bernardgreen]

We don't even know whether the house owner also owns the shop/business.

House owner owns the shop but not the business conducted there.

And with apologies to Bernard for going further off topic:

No problem, your input is extending the subject to wider applications so is good

 

[PBC_1966]

Is EDF entirely state-owned?

So far as I'm aware, yes. It was created as a state-owned utility after the war, and I don't think it's been privatized at all.

If there were 'public shareholders', I might have expected them to moan about policies designed to restrict the sales, hence profits! ... and I'd say the same about PG&E!

PG&E is private, but quite heavily regulated by the California Public Utilities Commission with regard to rates. And there's the whole California energy crisis business in recent years.

 

[JohnW2]

Is EDF entirely state-owned?

So far as I'm aware, yes. It was created as a state-owned utility after the war, and I don't think it's been privatized at all.

Thanks. That's what I thought.

If there were 'public shareholders', I might have expected them to moan about policies designed to restrict the sales, hence profits! ... and I'd say the same about PG&E!

PG&E is private, but quite heavily regulated by the California Public Utilities Commission with regard to rates. And there's the whole California energy crisis business in recent years.

Interesting. How keen are people (and, more to the point, institutions) to be become shareholders in a company which is deliberately restricting/discouraging growth and profitability (even if that is forced upon them by regulation)??

Kind Regards, John

 

[ericmark]

MCB supplying the shop is a B32 and not 16 amps as first though so what were the staff in the shop using to trip that ?.

I would guess some one has done something silly, realised what they have done, and are unlikely to admit to anyone what it was. I had a problem with staff turning off the storage heater as some days it got too warm and using fan heaters instead. At night they could use 300 amp if they wanted without a problem but during the day we were right on the limit with all the machines running and 5 offices with fan heaters all on one phase could take us over the limit hence use of storage heaters. If there was a power cut they would hide the fan heaters as they knew they should not be using them.

They thought I was being nasty when I swapped the B32 for a B20 but really it was because some one had extending the 4mm² radial using 2.5mm² cable so I changed the MCB to prevent the cable being overloaded. It was an old Wylex board and I actually found on a few times some one had put a 32A MCB back in, I had not bothered changing the holder red to yellow as had intended to renew the cable once I got time.

With 2 x 16A and 1 x 6A off a 32A supply it would be hard to overload unless using loads of tungsten lighting so would thing some one did something which they are not admitting to?

 

[ban-all-sheds]

Fair enough. However, AFAIAA, that situation has existed for decades. If they had wanted to grow their business and hence increase profits, one would have expected them to have invested in improving the infrastructure - so that, just like almost every other company who sells things, they could then have spent their time encouraging, rather than discouraging, customers to buy more of their product!

They charge the same per kWh for everyone, and higher prices for higher capacity.

I think that is a very good solution, and much better than "investing" in extra infrastructure, with all the environmental damage that entails, in order to build an infrastructure that might not be needed.

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"!

They don't and it isn't.

It's a charge to have access to a share of their infrastructure. Look at the rate per kW of that charge.

How keen are people (and, more to the point, institutions) to be become shareholders in a company which is deliberately restricting/discouraging growth and profitability (even if that is forced upon them by regulation)??

Encouraging people to use more and more electricity and gas is utter madness.

 

[JohnW2]

They charge the same per kWh for everyone, and higher prices for higher capacity. .... It's a charge to have access to a share of their infrastructure. Look at the rate per kW of that charge.

From the consumer's point of view, that's little more than a 'paper exercise'. What matters to them is the overall effective cost per kWh (taking standing charge into account). For a French consumer using 6,400 kWh per year (allegedly the average French domestic consumption - see here ) that effective cost per kWh (for all their electricity) would rise from 0.1552 euros if they only wanted a peak supply of 3kW/15A to 0.1838 euros if they wanted a peak supply of 18kW/90A (comparable with the 'usual' UK domestic supply). This price structure is arguably particularly unfortunate ('unfair'?) for a consumer with very modest total electricity requirements, but occasional short-term high loads (e.g. a shower?).

I dare say there are probably provisions for preventing this being exploited, but the EDF figures posted suggest that it would actually be cheaper in France to have multiple "3kW" supplies than to have one 9, 12 or 15 kW supply!

I think that is a very good solution, and much better than "investing" in extra infrastructure, with all the environmental damage that entails, in order to build an infrastructure that might not be needed.

Environmentally, that's probably correct. I was commenting on the 'business model', which is pretty unique.

Encouraging people to use more and more electricity and gas is utter madness.

Environmentally, that's probably correct. I was commenting on the 'business model', which is pretty unique.

If promotion ('encouragement of more use'), or even sale, of everything which had a negative effect on the environment or on public/individual health was 'outlawed', we would be living in a very different world! It's also interesting that, if the figures in the above link are to be believed, the average domestic electricity consumption in France (6,400 kWh/year) is about 39% higher than the figure given for the UK (4,600 kWh/year), despite the French price structure.

My comment about 'business models' was merely stimulated by the fact that I really can't think of any other common situation in which one is expected to pay more (per unit of purchase) if one wants to buy more of a particular product. The normal expectation is, of course, the converse of that.

Kind Regards, John

 

[Spark123]

My guess is a faulty appliance was plugged in. What else does the craft shop have? Out of interest, do they have a kiln?

 

[JohnW2]

My guess is a faulty appliance was plugged in.

Now that we know that the house MCB is a 32A one, that is clearly now quite probable, assuming there are no other high loads we have not been told about. A (non-faulty) 2kW heater plus a (non-faulty) 3kW kettle obviously would not trip a 32A MCB, even if both were on continuously.

Kind Regards, John

 

[JohnW2]

I think that is a very good solution ...

It occurs to me that you and I have seemingly both previously agreed that OPDs should not be used to 'limit the load' - but that appears to be what the French are doing.

Kind Regards, John

 

[bernardgreen]

No kiln and so far no admissions from staff about anything having happened such as duff equipment being plugged in The house owner is letting it drop unless ( or until ) it happens again.

It has a parallel to my situation as one of my outbuildings is rented to a florist with a feed from my cottage. But she has a key and permission to go in if necessary.

 

[JohnW2]

No kiln and so far no admissions from staff about anything having happened such as duff equipment being plugged in The house owner is letting it drop unless ( or until ) it happens again.

Fair enough. As I wrote recently, it now seems to be that either 'duff equipment' was plugged in or else there were appreciable loads in addition to what you've been told about.

Kind Regards, John