Is neutral typically provided to European control panels?

agarb

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May 2006
Location
USA
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In my experience, most of the control panels I have seen here in the USA require 480 VAC, 3 phase and (typically) no neutral is required/supplied. Then, internal to the control panel, a small transformer is used to step down to 120VAC single phase that is used to power small DC power supplies, cooling fans, laptop for programming, etc.

How does this compare to the EU?

My understanding is that a harmonised 400VAC, 3 phase is typically supplied to industrial control panels. If a neutral was provided, then 230 VAC would also be readily available. But is a neutral typically furnished to control panels thereby eliminating the requirement to supply a small transformer to power devices such as power supplies, cooling fans, laptop for programming?

If anyone has some pdf schematics for European equipment they can share, I'd love to take a peak at some power distribution examples for industrial control panels.
 
All depends on the site.

If only 400v 3 phase is available then we fit a control transformer or psu in the same way.

If 3 phase + a neutral is available then we can run single phase equipment without the need.
 
I don't have any docs I can share, but one of my colleagues recently got back from a job in the EU, and was raving about how convenient the neutral in the cabinet was.

I'm sure it depends project to project, though.
 
My understanding is that a harmonised 400VAC, 3 phase is typically supplied to industrial control panels. If a neutral was provided, then 230 VAC would also be readily available. But is a neutral typically furnished to control panels thereby eliminating the requirement to supply a small transformer to power devices such as power supplies, cooling fans, laptop for programming?

I've worked on a few machine that used 400VAC and neutral to run a panel as 230VAC and balance the load across the the devices (drives/motors) and contained nothing that ran on 400VAC. What surprised me is that the company that purchased the European equipment installed a huge transformer to supply the required 400VAC rather than request the panel to be wired for 230VAC and supplied enough Amps to handle it.

I may be missing something.
 
I have not used the neutral in electrical designs for at least 20 years.

The most recent three-phase industrial electrical installations are already made without neutral.

Using the neutral is less safe, long time ago I saw equipment destroyed by a fortuitous disconnection of the neutral.

The best practice is not to use neutral.
 
Neutral in virtually every switch board in Australia. MEN system used here - no issues at all.
 
I would say that it is very common. BUT if you have a very large current draw in the panel then the size of the cable supplying the cabinet would be large, then it could be economical to use 3x400 instead of 3x400+N since you can buy a cheaper cable with one less conductor.
 
For us it depends on the type of installation. Usually we don't have Neutral. We always fit an isolating transformer for our own 230 VAC control voltage.

Some installations have equipment that require 3x400+N, but (for us) that is less than 10%.
 
OK, you have made me think, thank you for that. There are both types of systems out there, 3 phase only and 3 phase plus Neutral and both work. Advantages/Disadvantages of each I will have to research. Be careful of getting 'well we do this' answers because they answer nothing unless they are backed up with evidence and reason. I guess I know what I will be doing this afternoon!!

B

edit: Sorry I didn't mean to be rude to the 'we do this' answers, sometimes/often I am lacking tact. I would be a lousy politician.
 
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I was always under impression that 3 phase + neutral (i.e. the supplying transformer secondary wired 'wye') is a standard throughout Europe while having no neutral (the transformer wired 'delta') is rather an exception.
 
I was always under impression that 3 phase + neutral (i.e. the supplying transformer secondary wired 'wye') is a standard throughout Europe while having no neutral (the transformer wired 'delta') is rather an exception.

There is always 3x400v+N but you don't necessary have to use it to supply equipment
 
In house installations you always have 3ph + N + PE.
In industrial installations it varies on the application.
N is normally only supplied if there are large 230V consumers, i.e. ligthing or heating or similar.
The 230V control voltage in control panels is almost always derived from 400V via a transformer. One reason is that you cant just take a large incoming supply with a lot of short circuit current and distribute it to 1.5mm wiring in the control system. You have to bring the short circuit current down, and the almost universal way to do it is via a transformer.
 
Thank you for the headache. I am not setting myself up as an expert, all the below is found with web searches.

There are advantages and disadvantages with Delta and Y/Star systems. Generally the transmission lines from generating station to local step down transformer are without a Neutral and so are derived from a Delta system, so here we are just talking about the last bit of the circuit.

Please feel free to add to the lists.

3 phase Delta advantages:
Only need three wires plus earth.
Can keep working with a single earth fault if a floating system.

3 phase Delta disadvantages:
If a floating system then it is harder to detect earth faults.
More difficult to safely earth.
Only one voltage available.


3 phase Y/Star advantages:
You have two voltages available, one higher and one lower.
Can supply a lot of single phase loads up to the full capacity of the system if the single phase loads are balanced between the phases.

3 phase Y/Star disadvantages:
Faulty Neutral can cause problems.
Needs four wires plus earth.

I don't want to cause controversy, much, but the European system of a grounded star system is of course the best. :)
Lets make Europe great again!!


References:
https://www.achrnews.com/articles/93448-more-delta-vs-wye-transformers

https://www.quora.com/What-is-the-s...What-happens-if-the-neutral-line-doesnt-exist

https://www.schneider-electric.us/e...-and-ungrounded-electrical-system-designs.jsp

https://www.physicsforums.com/threads/delta-vs-wye-pros-and-cons.682676/

https://www.youtube.com/watch?v=3ktxtDW6UAE

http://electrical-engineering-portal.com/delta-star-transformer-connection-overview
 
We all talk from our own experience, Jesper is obviously working in 'big' industry and so adding a transformer to bring down the short circuit current makes sense. I work in 'small' industry with fractional horsepower/kilowatt motors and small heaters where the extra space requirements and heat output of a transformer would cause problems. So for me having 240V available to run some of the control circuit makes much more sense.
 
In Singapore, they supply 400V 3PH + N + PE to the panels.
The neutral provides 230V from any 1 of the 400V lines. That is where I get the 230V Control voltage. This prevents the need for a 3-5 KVA control transformer in the enclosure.
I do not want to discuss how "clean" this 230V power is....but I only use it to power Main Power relays, Motor Control relays / aux contacts....from there I go to 24VDC for PLC and IO...which is now clean power.

I see this as a advantage compared to the US, we have to use a control transformer on our 440-480VAC to get to 115V for controls.
 
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