Practicality of 400 volt equipment

[Cookie]

Would it be practical, or technically possible to economically mass produce 400 volt single phase consumer goods? Light bulbs, kettles, heaters, chargers, TVs, hobs, vacuum cleaners, washers, dryers, microwaves, tools, ect ect?

I'm thinking this would save a lot of copper and make wiring both easier and safer. A 1mm2 cable on a 10 amp breaker would give 4,000 watts of power.

 

[Pete999]

Would it be practical, or technically possible to economically mass produce 400 volt single phase consumer goods? Light bulbs, kettles, heaters, chargers, TVs, hobs, vacuum cleaners, washers, dryers, microwaves, tools, ect ect?

I'm thinking this would save a lot of copper and make wiring both easier and safer. A 1mm2 cable on a 10 amp breaker would give 4,000 watts of power.

I'm confused Mate by your conclusions.

 

[R-fur]

UK regulation 559.5.1.201 limits lamp holders to 250V.
The biggest cost with cable is usually the installation so reducing the cable size would not save that much. 400V accessories would be bigger and more expensive.

 

[Julie.]

It doesn't really matter, different places may settle on different voltages to suit their situation, higher voltages will have issues/costs associated with risk of shock or additional insulation needs etc. Lower voltages with lower shock risk, higher losses and additional costs of conductors etc.

What balance you choose is up to you. In the main internationaly the standard throughout the world is in the 200-250v range - commonly 230v .

This is generally the best balance between all the factors, now it is the main standard most equipment is designed for this voltage, therefore more countries use it, so it's more of a standard, etc.

However there are some countries that are an exception to that in the 110/117v range, these are often purely historical, but once again once in this loop standard voltage - more products - more of a standard etc.

 

[Cookie]

I'm confused Mate by your conclusions.

400 volt single phase delivers more power for the copper; also dispensing of the need for a neutral (5th wire) within the installation further saves cost plus all the safety benefits of coming from a TN-S supply.

 

[Cookie]

UK regulation 559.5.1.201 limits lamp holders to 250V.
The biggest cost with cable is usually the installation so reducing the cable size would not save that much. 400V accessories would be bigger and more expensive.

Can't T&E take 230 volts line to earth? How much does 1mm2 T&E cost vs 2/5mm2 T&E per meter?

 

[Cookie]

It doesn't really matter, different places may settle on different voltages to suit their situation, higher voltages will have issues/costs associated with risk of shock or additional insulation needs etc. Lower voltages with lower shock risk, higher losses and additional costs of conductors etc.

What balance you choose is up to you. In the main internationaly the standard throughout the world is in the 200-250v range - commonly 230v .

This is generally the best balance between all the factors, now it is the main standard most equipment is designed for this voltage, therefore more countries use it, so it's more of a standard, etc.

However there are some countries that are an exception to that in the 110/117v range, these are often purely historical, but once again once in this loop standard voltage - more products - more of a standard etc.

Agree. Though would 400 volt as a standard cost more then having 230 volts as a standard?

 

[DPG]

Bizarre idea. And why stop at 400V? Go for 1500V and save even more copper!!

 

[Cookie]

Bizarre idea. And why stop at 400V? Go for 1500V and save even more copper!!

400 volts is already in place, above 1000 volts installations require significantly more complex insulation for guard against partial discharge plus the disconnection times would be difficult if not impossible to achieve.

 

[Julie.]

400 volts is already in place, above 1000 volts installations require significantly more complex insulation for guard against partial discharge plus the disconnection times would be difficult if not impossible to achieve.

Why - many large industrial sites use 3.3kV motors and so on.

The voltage isn't fixed at 230 (or 110) - that's just the most suitable for most end users taking into account the factors.

Like why we use 3 phase and not 7 phase and so on - it achieves the best balance given the technology we have

 

[Cookie]

Why - many large industrial sites use 3.3kV motors and so on.

The voltage isn't fixed at 230 (or 110) - that's just the most suitable for most end users taking into account the factors.

Like why we use 3 phase and not 7 phase and so on - it achieves the best balance given the technology we have

Right, but 3.3kv with EPR insulation, stress cones and OCPDs to achieve rapid disconnection. The added cost and complexity would outdo any copper savings of using 3.3kv in residential and commercial.

400 volts on the other hand uses PVC insulation and at 230 volts to ground can use standard MCBs.

 

[Julie.]

Right, but 3.3kv with EPR insulation, stress cones and OCPDs to achieve rapid disconnection. The added cost and complexity would outdo any copper savings of using 3.3kv in residential and commercial.

400 volts on the other hand uses PVC insulation and at 230 volts to ground can use standard MCBs.

but if you are going to start using phase to phase voltages, then you must start distributing 3 phase supplies - that's a two fold increase in the amount of copper used, plus all switchgear would be three phase etc.

That is a significant increase in costs - a 1.73 reduction in cable size balancing a 2 fold increase in the number of cables

 

[Cookie]

but if you are going to start using phase to phase voltages, then you must start distributing 3 phase supplies - that's a two fold increase in the amount of copper used, plus all switchgear would be three phase etc.

That is a significant increase in costs - a 1.73 reduction in cable size balancing a 2 fold increase in the number of cables

No necessarily- you could drop two phases and an earth at each property.

100 x 230 =23,000va / 400 volts= 57.5 amps or 63 amp main fuse.

3 phase would give 33 amps per phase or a 35 amp main fuse.

In both cases the main would use thinner copper, and in the 3 phase example the number of wires do not change in that a 4th neutral is provided as is.

 

[Julie.]

No necessarily- you could drop two phases and an earth at each property.

100 x 230 =23,000va / 400 volts= 57.5 amps or 63 amp main fuse.

3 phase would give 33 amps per phase or a 35 amp main fuse.

In both cases the main would use thinner copper, and in the 3 phase example the number of wires do not change in that a 4th neutral is provided as is.

In which case you cannot use 230V equipment!

it's only 400V in relation to a three phase circuit - each breaker is only operating at 230V if you use a single breaker then it must be 400V

All UK domestic equipment is 230v, switches etc

Yes SOME industrial kit is rated at 660V - but even that isn't sufficient, you would need 800v three phase kit for each breaker to open single phase 400V (700V but that's not standard)

A three phase set of breakers does not mean each is capable of opening 400V

 

[Pete999]

Why - many large industrial sites use 3.3kV motors and so on.

The voltage isn't fixed at 230 (or 110) - that's just the most suitable for most end users taking into account the factors.

Like why we use 3 phase and not 7 phase and so on - it achieves the best balance given the technology we have

Sorry Julie disagree with your reasoning

 

[Julie.]

Sorry Julie disagree with your reasoning

In what way?

 

[Pete999]

In what way?

Your reasoning shows no essence just random wording.

 

[rapparee]

Nobø Front 400V | Nobo

en.nobo.no

It already exists.

 

[Julie.]

Your reasoning shows no essence just random wording.

Well I thought it made sense!

It is still possible to use any voltage you want to suit your purpose, yes there are standards such as 230/400, or 380/660, or 1000v as per iec 60038.

However the 230/400 is most common purely because for the most part the current levels are manageable i.e cable sizes, the insulation needs are not onourous and most simple circuit breaker technologies can handle it.

That's why it has become the standard from all the options.

In the same way three phase makes the most sense - its more efficient than single or two phase, but also no less efficient than 4, 5,6,7.... phase.

Does that make it clearer?
[automerge]1600022035[/automerge]

Nobø Front 400V | Nobo

en.nobo.no

It already exists.

There are lots of equipment that is single phase 400v - but its usually just in industrial settings, for example control transformers are usually phase to phase as there often isn't a neutral.

I took the op to mean why don't we use 400v across the board as standard rather than 230v

 

[Cookie]

In which case you cannot use 230V equipment!

it's only 400V in relation to a three phase circuit - each breaker is only operating at 230V if you use a single breaker then it must be 400V

All UK domestic equipment is 230v, switches etc

Yes SOME industrial kit is rated at 660V - but even that isn't sufficient, you would need 800v three phase kit for each breaker to open single phase 400V (700V but that's not standard)

A three phase set of breakers does not mean each is capable of opening 400V

Right.

400 volt rated switches, sockets and light fittings.

Two and 3 pole breakers are already slash rated 230/400Y.

 

[Cookie]

Nobø Front 400V | Nobo

en.nobo.no

It already exists.

Are the coils 400 volts or just multiple 230 volt coils?

 

[westward10]

Your reasoning shows no essence just random wording.

I have absolutely no idea why you disagree with @Julie. and your response is quite frankly ridiculous.

 

[Julie.]

Right.

400 volt rated switches, sockets and light fittings.

Two and 3 pole breakers are already slash rated 230/400Y.

In terms of iec equipment 230/400 refers to 230v ph - e/n and 400v ph-ph

They are only suitable for 400v if they are multiple pole.

 

[Cookie]

Well I thought it made sense!

It is still possible to use any voltage you want to suit your purpose, yes there are standards such as 230/400, or 380/660, or 1000v as per iec 60038.

However the 230/400 is most common purely because for the most part the current levels are manageable i.e cable sizes, the insulation needs are not onourous and most simple circuit breaker technologies can handle it.

That's why it has become the standard from all the options.

In the same way three phase makes the most sense - its more efficient than single or two phase, but also no less efficient than 4, 5,6,7.... phase.

Does that make it clearer?
[automerge]1600022035[/automerge]


There are lots of equipment that is single phase 400v - but its usually just in industrial settings, for example control transformers are usually phase to phase as there often isn't a neutral.

I took the op to mean why don't we use 400v across the board as standard rather than 230v

6 phase is actually more efficent, but I've read that its not worth the extra complexity.

If we were to mass produce 400 volt consumer products, would it be more expensive than 230 volt consumer was my primary questions- though its not really confined to that only. Anything and everything is open to discussion around this subject.

In terms of iec equipment 230/400 refers to 230v ph - e/n and 400v ph-ph

They are only suitable for 400v if they are multiple pole.

True. The only thing that will need to be re-designed are single pole switches.

 

[rapparee]

Are the coils 400 volts or just multiple 230 volt coils?

A 400v element is inside it along with 400v controller

We manufacture it for the Scandinavian market

 

[Cookie]

A 400v element is inside it along with 400v controller

We manufacture it for the Scandinavian market

These heaters are these start of something great! Do you have pictures of the internals by chance? What electronic components (rating/type) you use on the circuit board? The tracks on the board? I'm assuming its directly across the mains.

 

[Julie.]

6 phase is actually more efficent, but I've read that its not worth the extra complexity.

If we were to mass produce 400 volt consumer products, would it be more expensive than 230 volt consumer was my primary questions- though its not really confined to that only. Anything and everything is open to discussion around this subject.




True. The only thing that will need to be re-designed are single pole switches.

Not really, the whole wiring systems are designed around 230/400v rather than 400v

Switches and breakers are the most obvious, but my whole point is there are and have been other voltages, but the balance of advantages/disadvantages appears to work out around the 230/400v mark which is why it has ended up being the voltage range of choice.

It may be that as technology advances, and we develop new materials, that this balance may actually move to higher, or lower voltages than it currently is, but then do you redevelop everything for a marginal gain.

Where it isn't a marginal gain, then equipment is chosen at different voltages - but such a choice comes at a cost.

I have worked on many sites where all industrial equipment is at 660v, 1000v, 1.5kV or 3.3kV etc in order to reduce the current over large distances, however the cost is limited choice of switchgear, cables etc.

Ultimately its best to have a single standard, which whilst isn't the most efficient in all cases is sufficiently efficient that the advantage of simplicity outweighs the complexity of multiple standards

 

[Cookie]

Not really, the whole wiring systems are designed around 230/400v rather than 400v

Switches and breakers are the most obvious, but my whole point is there are and have been other voltages, but the balance of advantages/disadvantages appears to work out around the 230/400v mark which is why it has ended up being the voltage range of choice.

It may be that as technology advances, and we develop new materials, that this balance may actually move to higher, or lower voltages than it currently is, but then do you redevelop everything for a marginal gain.

Where it isn't a marginal gain, then equipment is chosen at different voltages - but such a choice comes at a cost.

I have worked on many sites where all industrial equipment is at 660v, 1000v, 1.5kV or 3.3kV etc in order to reduce the current over large distances, however the cost is limited choice of switchgear, cables etc.

Ultimately its best to have a single standard, which whilst isn't the most efficient in all cases is sufficiently efficient that the advantage of simplicity outweighs the complexity of multiple standards

You're forgetting the history. The world started off with 110-127 volts. Eventually 127/220 in that 110-127 volts was just to low as it could not meet the needs to heaters and motors. Then came the discovery that the advantages associated with 220 volt could be extended to small equipment and associated branch circuits. 220 became the norm- hence why the schuko plug is not polarised.

When 220 volts became the norm for all single phase equipment, people realized that 220/380 met the needs of ever larger motors in typical buildings and long public supplies.

The thing is, today we are stuck on a dual voltage system without any investigation made if 400 volt single phase equipment might be more practical than 230 volt equipment.

 

[Julie.]

You're forgetting the history. The world started off with 110-127 volts. Eventually 127/220 in that 110-127 volts was just to low as it could not meet the needs to heaters and motors. Then came the discovery that the advantages associated with 220 volt could be extended to small equipment and associated branch circuits. 220 became the norm- hence why the schuko plug is not polarised.

When 220 volts became the norm for all single phase equipment, people realized that 220/380 met the needs of ever larger motors in typical buildings and long public supplies.

The thing is, today we are stuck on a dual voltage system without any investigation made if 400 volt single phase equipment might be more practical than 230 volt equipment.

No, not forgetting, but the first generation and distribution of electricity was in the uk in the 1880s it distributed ac 250v and 40v for different types of lighting.

I think it was in Godalming

Next was 110v dc in London


I certainly don't think we arrived at ~230v by accident without any thought, in Germany for example they specifically altered all their equipment from 127v to 240v to take advantage of the lower current, without too many issues with high voltage - other countries followed similar changes settling at various voltages mainly in the 200-250v for household and higher for industrial.

The compromise of 230v is fairly recent in those terms

 

[Cookie]

No, not forgetting, but the first generation and distribution of electricity was in the uk in the 1880s it distributed ac 250v and 40v for different types of lighting.

I think it was in Godalming

Next was 110v dc in London


I certainly don't think we arrived at ~230v by accident without any thought, in Germany for example they specifically altered all their equipment from 127v to 240v to take advantage of the lower current, without too many issues with high voltage - other countries followed similar changes settling at various voltages mainly in the 200-250v for household and higher for industrial.

The compromise of 230v is fairly recent in those terms

What investigation is there of 400 volts? Remember that incandescent bulbs no longer play a role where high voltages mean higher gas fills and thinner, longer, cooler running filaments. LEDs can be fed via driver. Caps and resistors can drop 400 volts to the required series parellel voltages.

 

[Julie.]

What investigation is there of 400 volts?

Write to the iet or iec and ask them.

 

[Lucien Nunes]

The gist of the OP's question is why not make the default single-phase voltage, i.e the lowest voltage available on the system, 400V rather than 230, regardless of the phase arrangement. So discount whether it's Y or delta, single or three phase, and just consider whether 400V light bulbs, hairdryers, phone chargers etc. are sensible and practical and worth the saving in copper.

The answer I suspect is no.

Historically, the choice of voltage was significantly dictated by both carbon-arc and filament lamp design and 120 years ago, both worked better at 120V than 240. Metal filament lamps are stronger, last longer and are more efficient at lower voltages (hence 12V halogens etc.) In the UK, we actually preferred 120V lamps in series pairs for certain stage lighting purposes instead of 240V and projector lamps were 120V fed from a transformer, because 230V lamps were so fragile and inefficient. We got good at making 230V general purpose lamps but 400V was basically unachievable, so there never was a 400V incandescent lighting option. None of that really applies in 2020.

The fragility argument also goes for many wound components, a small 400V transformer primary or relay coil is more expensive to make and more prone to failure than a 230V one, due to having many turns of very fine wire. Even 230V can be a problem - many small mechanical timeswitch motors (e.g. the defrost timer in the freezer and plug-in timers) actually used a 120V or lower voltage motor, fed by a capacitor dropper, because a 230V type would be too expensive and fragile. 400V would be much more of a problem still.

Discharge lamps with ballasts dictate their own voltage and the ballast takes up the difference between that and the supply. So a metal halide lamp running on 400V will take the same current as one on 230V, just at a lower power factor as the (more expensive) ballast has to drop an extra 170V. Only a transformer would solve this.

But, the main event is the switched-mode power supply, where the electronics on the primary side have to operate at the peak voltage of the supply. In most electronic devices, and any appliances containing electronics, the incoming 230V AC is rectified and smoothed to 320V DC, whereas on 400V the DC rail would be 560V. This requires both smoothing capacitors and chopper transistors of a different tier of performance, which certainly with the components available today would significantly impact the price. 560V is definitely at the top end of what electrolytic capacitors are capable of, and at this voltage it is not uncommon to have to use series pairs with balancing resistors. Possible, but probably not economic, given that many such power supplies use so little power that they would not contribute to any realistic saving in copper. Really small loads that use capacitor droppers, like the ballasted discharge lamps, would simply have to use a more expensive capacitor and drop more volts, with no saving in current.

Therefore I think with the state of the art, small power and lighting is still best served in the 120-230V range, with advantages to both voltages but increasingly in favour of 230V now that filament lamps are not a driving factor.

 

[Simon47]

Given that the idea of switching to 400V delivered as 2 legs of a 3P system, I'm surprised there's been no discussion about how the change coukd be made. It makes me think of the old joke about the tourist asking a local how to get somewhere - only to be told "I wouldn't srart from here".
With the change, single phase systems would now have two line conductors - so you now need 2 pole protection and switching for everything. So you're no needing a partial rewire of every property. Lights looped at the rose now need altering to take the second line down to the switch & back - physically you may be looping at the rose, but electrically the same as looping at the switch and needing a partial rewire. And of course, you'll need to replace most of your accessories to make everything 2 pole switched. And all your plugs will need replacing for ones with 2 fuses - I remember they had some of those at school for the 110V stuff run from 55-0-55V supplies.
So we've replaced all the CUs, partially rewired, replaced most of our accessories and pkugs and ... we still haven't addressed appliances.
So we also persuade everyone to replace their fully servicable appliances for new ones designed for the higher voltage. And they will be new ones as no supply of second hand ones. The day someone suggests that to me, they will learn some "interesting" vocabulary - unless they are offering to pay for it all.

Of course, there is the alternative of adding a stwp down isolating transformer between the meter and CU - at a cost, and if there's room in the modern shoeboxes.

And what do we gain ? Absolutely nothing at all until EVERY custoner on part of the network has been converted.

Conversely, any custoner is free to ignore the DNO provided earth and make their own arrangements - limited only by their access to sonewhere for a suitably earth electrode (system).

Lastly, who here has has the experience of connecting a 110V item to 240V ? Occasionally it's forgetting to check the position of the voltage selector switch. Once in my case it's been someone sending me the wrong (single voltage) part. But generally the results "aren't pretty".
So I would forsee a lot of blown up kit as people plug their 240V items into 400V supplies. Now they wouldn't ? I can assure you that a lot if oeople would - they have no idea what voltage is.
I recall at a previous place, the ladies in the retail shop asked the maintenance guy for some wire cutters. Why ? To cut off the plug and fit a new one on the christmas tree lights - it never occurred to then that the reason for an "odd" plug could be that the lights weren't 240V.

So, woukd 400V be a good idea ?
Possibly - but only if you don't start from here!

 

[Cookie]

You would not need 2 pole switching except at the consumer unit.

 

[James]

You would not need 2 pole switching except at the consumer unit.

For functionality you are correct, for safety I would disagree.

 

[Lucien Nunes]

It doesn't have to be two legs of a 400/230V system. One night, the DNO could uplift your local 400/230V transformer and drop a 690/400 in its place, and presto! 400V Uo in your house.

Switchovers from one voltage or frequency to another and DC to AC have all been done before. When the National Grid drove a rollout of standardised voltage and frequency, electricity suppliers would take your appliances and either modify them for the new supply or replace it if not possible, just as gas appliances were converted from town gas to natural gas. In the museum we have appliances originally made for non-standard voltages that have been reworked and the new voltage engraved onto the plate. E.g. a Hoover vacuum cleaner made for 210V that had a replacement armature fitted and '240V' stamped over the 210. Until recently, a church with a 1920s organ blower wound for 200V was running it from 400 via a transformer supplied and fitted in the 1940s at the electricity supplier's cost. Sites with large inventories of DC plant used to install rectifiers to keep it all running when the mains were converted to AC.

The greater number of appliances in use today and the impracticality of converting most of them makes a repeat of that exercise near impossible, though.

 

[Cookie]

For functionality you are correct, for safety I would disagree.

What safety comes from using a wall switch as a disconnecting means?

 

[Cookie]

It doesn't have to be two legs of a 400/230V system. One night, the DNO could uplift your local 400/230V transformer and drop a 690/400 in its place, and presto! 400V Uo in your house.

Switchovers from one voltage or frequency to another and DC to AC have all been done before. When the National Grid drove a rollout of standardised voltage and frequency, electricity suppliers would take your appliances and either modify them for the new supply or replace it if not possible, just as gas appliances were converted from town gas to natural gas. In the museum we have appliances originally made for non-standard voltages that have been reworked and the new voltage engraved onto the plate. E.g. a Hoover vacuum cleaner made for 210V that had a replacement armature fitted and '240V' stamped over the 210. Until recently, a church with a 1920s organ blower wound for 200V was running it from 400 via a transformer supplied and fitted in the 1940s at the electricity supplier's cost. Sites with large inventories of DC plant used to install rectifiers to keep it all running when the mains were converted to AC.

The greater number of appliances in use today and the impracticality of converting most of them makes a repeat of that exercise near impossible, though.

What was the highest single phase voltage ever used in the UK or anywhere in the world?

 

[James]

What safety comes from using a wall switch as a disconnecting means?

It is often, although not always that an isolator next to an appliance is not only a functional switch but also an isolator.
An oven or a shower would be a couple of things that spring to mind.
It would be unexpected for part of the appliance to remain live after you had switched it off

 

[Simon47]

It doesn't have to be two legs of a 400/230V system. One night, the DNO could uplift your local 400/230V transformer and drop a 690/400 in its place, and presto! 400V Uo in your house.

But in the context that started this off, getting rid of combined neutral & earth, doing that wouldn't really help.

Switchovers from one voltage or frequency to another and DC to AC have all been done before.

Indeed, but back then there weren't huge numbers of appliances - and what there were would have been "properly built". As you point out ...

The greater number of appliances in use today and the impracticality of converting most of them makes a repeat of that exercise near impossible, though.

Indeed. Though I'd have gone further than "near impossible" ! I couldn't see it being done in any other way than lots of transformers. Just a very quick count around the house quickly heads up past 50, before I've included lights and fixed stuff like the boiler. Quite a lot of fixed stuff - PIR detectors, lights, heating controls, pumps, and the list goes on and on.

I think a lot of 25kVA transformers needed ![/QUOTE][/QUOTE]