3 Phase or 1 Phase Supply?

[JohnW2]

At the end of last year, I went onto npower fixed deal. It has no standing charge. It's replacement has the standing charge back!

Was that a true 'no standing charge' or was there, like with my previous one, a surcharge for the first N units?

Kind Regards, John

 

[plugwash]

OK - I thought it was standard practice to have a higher standing charge.

It would be quite difficult for them to justify. Apart from the trivial fact that a 3-phase meter is presumably marginally more expensive, and that they would need a metre or two more of tails to install it, I can think of nothing which, from the supplier's viewpoint, makes a 3-phase supply any more expensive to administer.

Out of curiosity does anyone know if the suppliers pay a "standing charge" to the DNO for each customer connected and if so whether it varies with the type of supply?

I would think that a three phase supply is quite a bit more expensive to maintain for the DNO. For example IIRC there is a problem with the cutout then for a single phase supply with a modern cutout/cable they can replace it live whereas with a three phase supply they are required to cut the service cable outside to isolate.

 

[AndyPRK]

At the end of last year, I went onto npower fixed deal. It has no standing charge. It's replacement has the standing charge back!

Was that a true 'no standing charge' or was there, like with my previous one, a surcharge for the first N units?

Kind Regards, John

No it was flat rate too. Amazing. Called price fix April 2015

 

[JohnW2]

Out of curiosity does anyone know if the suppliers pay a "standing charge" to the DNO for each customer connected and if so whether it varies with the type of supply? I would think that a three phase supply is quite a bit more expensive to maintain for the DNO.

That's a point, and I don't know what the answer is. Don't forget, though, that for both DNO and supplier, a 3-phase supply will usually be associated with more consumption than a single-phase supply, hence more profit - so the higher costs of maintaining a 3-phase supply might be offset against that.

For example IIRC there is a problem with the cutout then for a single phase supply with a modern cutout/cable they can replace it live whereas with a three phase supply they are required to cut the service cable outside to isolate.

That makes sense, if one has a 3-phase cutout. However, I don't imagine that it would be an issue for my flavour of 3-phase supply, since 'the cutout' consists of three separate fuse holders, fed by singles (overhead supply), any one of which I imagine could be replaced live:

Untitled

• JohnW2
• 5 Apr 2012
• 3

Kind Regards, John

 

[westie101]

Out of curiosity does anyone know if the suppliers pay a "standing charge" to the DNO for each customer connected and if so whether it varies with the type of supply?

It varies on type of customer, the below is mainly for higher capacity users. For domestic and light commercial type metering it is a % charge on units used
http://www.smartestenergy.com/Power-Purchase/Products/Feed-in-Tariffs/GDUos-and-DUoS.aspx

DUoS (import) charges vary by voltage but can include: capacity and excess capacity charges (pence/kVA/day); fixed charge (pence/MPAN/day); energy charge unit rate (pence/kWh); excess reactive power charges (pence/KVArh).

Which is the same charging system as the days of the Electricity Boards

However, I don't imagine that it would be an issue for my flavour of 3-phase supply, since 'the cutout' consists of three separate fuse holders,

Correct

 

[ban-all-sheds]

I imagine it's less easy when there's a highly competitive market and a regulator looking over one's shoulder.

Yup.

And were there a highly competitive market and a regulator of more use than a chocolate teapot then it would indeed be less easy to get away with unjustified tariff structures.

 

[ban-all-sheds]

High power welding kit will require a network design to ensure the use of the welders does not interfere with the supply to other customers.

Is that just that high power welders cause voltage sag, or is it waveform distortion?

 

[JohnW2]

I imagine it's less easy when there's a highly competitive market and a regulator looking over one's shoulder.

Yup. And were there a highly competitive market and a regulator of more use than a chocolate teapot then it would indeed be less easy to get away with unjustified tariff structures.

Indeed, but as I wrote to Andy, there are two parts to that statement. Whilst it is certainly true that we currently don't have an effective regulator, we do have a 'highly competitive market', and that's probably a much more powerful factor than any regulator we're likely to see any time soon!

Kind Regards, John

 

[westie101]

Is that just that high power welders cause voltage sag, or is it waveform distortion?

Large flicker effects as the arc is struck, striking current can be in the order of 9x running current and is classed as frequent.

I had one a few years ago where a farmer was complaining that as he was welding all the lights in the farm house were nearly going out. He was being a bit obtuse as he would not accept the problem was of his own doing as it was all on one supply.
However as the voltage was going a bit too low at times for other reasons we fitted a voltage regulator which eased the problem.

 

[Monkeh]

High power welding kit will require a network design to ensure the use of the welders does not interfere with the supply to other customers. This could push the bill up if other work is required.

Don't be tempted not to declare the welders as if you connect them and complaints arise the DNO has the power to require you to not use them or disconnect your supply if you fail to comply

Just what is considered high power?

 

[westie101]

Just what is considered high power

A bit of a piece of string that one, but generally those above a 5kVA rating.

See the advice below

http://www.enwl.co.uk/docs/connections/guidance-for-interference-with-supply.pdf?sfvrsn=3

Electric Welders
An application for connection for welding purposes should state clearly the type, rating and supply voltage of the welding equipment before any arrangement is made for its installation. The connection of welding equipment is subject to the following factors that will be taken in to account on receipt of an Application form.

(a) Welders for connection between phase and neutral lines (nominally 230V) can be accepted for ratings only of 5kVA and below.

(b) Welders above 5kVA rating where the connection to the customer is not at high voltage should be connected
between phases of the three-phase supply (nominally 400V).

(c) Provision should be made for the correction of the power factor of the installation, which, because of the connection of welding equipment, may be unduly low The foregoing factors are applicable to most parts of Electricity North West’s electricity distribution network but there may be special cases where even these factors will be subject to modification.

(d) Welders, such as resistance types, having high ratings may require a supply delivered to the premises at high voltage and are the subject of special negotiations with Electricity North West for each individual case

However this should not be seen as carte blanch to just connect welders without consulting the DNO as even those below 5kVA can cause issues on some parts of the network

 

[Monkeh]

I shall have to ask very nicely before assaulting the local supply with my new welder, then.