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Topic Title: voltage optimisers
Topic Summary: Relationship with 17th edition
Created On: 26 October 2009 09:56 PM
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 26 October 2009 09:56 PM
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colin mccormack

Posts: 2
Joined: 25 July 2008

I have great concerns about the installation of a 300kva voltage optimisers at my work place and its subsequent relationship with the wiring regulations.
On installation of a voltage optimiser in front of a main switchboard (for example) then the characteristics of all outgoing circuits from that switchboard have been altered(ie loop impedance values, volt drop etc)due to the newly introduced impedance of the voltage optimiser.
Under the 17th edition regulations any alteration to an existing circuit must be incompliance with 17th edition.This means all the above outgoing circuits must then comply with 17th edition.As it is an older installation this is clearly impractical.

When carrying out periodic testing on the installation what values of loop impedance does the person doing the testing use?
The loop impedance values in the regs are all based on 230volts not the 220output voltage of a typical voltage optimiser.
These are just some of my reservations about this technology.
I would welcome any comments.
 26 October 2009 10:09 PM
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Testit

Posts: 2962
Joined: 06 August 2007

Off the cuff 2 things come to mind..
    Failure of the optimiser
    ADS and optimiser impedance


For the 10V difference in Uo values . 32amp B breaker = 230/160 and 220/160 which is approx 1.44 and 1.38 or 1.15 and 1.1 so only a difference of 0.05ohms.... So if you are within 0.05ohms of your Zs max likley the circuit has some issues anyway....

The impedance of the optimiser could alter things somewhat.. but you didnt mention what it is..

Some figures would be useful... given the impedance of the optimiser you should be able to tell at a glance if the circuits are still compliant...

Edit: When doing a periodic take a Zs reading and use a 220 Uo value if that's what the supply is... if in doubt it's £250 a day or £33 / hour including traveliing time and expenses

-------------------------
Online Services - http://propertydevelopment.org.uk

Experience can sometimes show that cost prevails over quality and safety, such little self-value that people hold.

Edited: 26 October 2009 at 10:22 PM by Testit
 27 October 2009 07:39 AM
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zeeper

Posts: 1409
Joined: 11 July 2008

I have great concerns about the installation of a 300kva voltage


And so you should, I have heard stories from other sites about what happens when these are fitted. And I suggest you look at the equation for "work done". Motors will run hotter, The lights will be dimmer thats if they come on at all. Any heating type things will take longer to heat up ,Extra Low voltage control circuits might not work consistantly, and on top of this you have the losses of the voltage optimisers its self. I am unconvinced and believe the whole thing to be a con.

Edited: 27 October 2009 at 07:50 AM by zeeper
 27 October 2009 12:56 PM
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tonysung

Posts: 630
Joined: 14 September 2001

The answer is out there ...

Sustainable Energy Saving Techniques for Existing Buildings: 11 November, 2009 (1.30pm-5.10pm)

Liverpool John Moores University,
Peter Jost Enterprise Centre, Byrom Street Campus
Contact Laurence Brady
l.j.brady@ljmu.ac.uk


Pre-registration

This is a free event sponsored by Liverpool John Moores University, CIBSE, IET and the Energy Institute. All guests (non-members) and members are very welcome and we hope you can make every effort to attend however spaces are limited and therefore pre-registration is essential.

Kind regards

-------------------------
Tony Sung
 27 October 2009 07:55 PM
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colin mccormack

Posts: 2
Joined: 25 July 2008

The answer is not out there!!
What is out there is a lot of talk about the pros and cons of whether voltage optimisers will actually save you money or not.
My concern is whether the users electrical installation is compliant with the IEE Regulations and is safe (under fault conditions) once the unit has been fitted. I also have concerns about how periodic testing
would be carried out post installation
I have raised these point with engineers from the NICEIC and they themselves were not clear on the matter.
 28 October 2009 01:52 PM
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AJJewsbury

Posts: 11374
Joined: 13 August 2003

My concern is whether the users electrical installation is compliant with the IEE Regulations

Might it be thought of as being similar to circuits supplied by an uninteruptable power supply? (which typically when being exposed to a load side fault will either immediately switch over to direct mains, collapse the output voltage to safe levels (small units only) or require the use of RCDs or/and supplementary bonding).

- Andy.
 28 October 2009 04:14 PM
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broadgage

Posts: 1282
Joined: 07 August 2007

Originally posted by: zeeper

I have great concerns about the installation of a 300kva voltage




And so you should, I have heard stories from other sites about what happens when these are fitted. And I suggest you look at the equation for "work done". Motors will run hotter, The lights will be dimmer thats if they come on at all. Any heating type things will take longer to heat up ,Extra Low voltage control circuits might not work consistantly, and on top of this you have the losses of the voltage optimisers its self. I am unconvinced and believe the whole thing to be a con.


Agree entirely, I also consider these devices to be a con.
Electronic lighting ballasts, switched mode PSUs and inverter motor drives will all draw more current at the lower voltage.
In some cases the extra current can be sufficient to trip the OCPD.
Of course there should be more of a margin than that, but in practice may not be.

And what happens if the DNO reduce the supply voltage to the legal minimum ? as they are entitlred to.
216 volts at the cut out.
215 volts input at the voltage optimiser.
195 volts output from the optimiser
183 volts at the farthest point of use
 10 November 2009 06:24 PM
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Backintime

Posts: 282
Joined: 11 April 2007

Originally posted by: colin mccormack

The answer is not out there!!

What is out there is a lot of talk about the pros and cons of whether voltage optimisers will actually save you money or not.

My concern is whether the users electrical installation is compliant with the IEE Regulations and is safe (under fault conditions) once the unit has been fitted.

I also have concerns about how periodic testing would be carried out post installation.

I have raised these point with engineers from the NICEIC and they themselves were not clear on the matter.


Clearly no one can give you an answer in the forum here.

Would it be useful to attend the seminar and ask questions to get clarification yourself?

Edited: 10 November 2009 at 09:31 PM by Backintime
 10 November 2009 06:54 PM
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GB

Posts: 357
Joined: 04 September 2002

Whos Voltage optimisation unit are you thinking of installing?
The impedance of the Voltage optimisation unit is "virtually nil" and although their may be an impact on Impedance with regards to the new installation (if required) this again is generally negligible.
With regards to whether they work I know of one installation where 17.5% saving were achieved on a 200K annual bill, so worth thinking about???????
 11 November 2009 01:51 PM
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chartassuk

Posts: 57
Joined: 25 July 2008

Hello colin,

May I suggest you search the Power forum, there are several topics discussing the merits or otherwise of voltage optimisers; Power Perfector being a brand that crops up frequently.
 14 November 2009 09:49 PM
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powercor

Posts: 6
Joined: 07 September 2009

Dear Colin

Have you manage to get any further information on installation of the voltage optimisation unit and has this unit been installed. We have recently installed a 300 KVA unit at a college and are achieveing good savings arround 13% but this is not true of all buildings and careful consideration must be taken of the existing load types.

Regards

Chris
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