Draft wiki article for comments

Since this has come up a few times recently, have a look at this and comment / edit as appropriate:
http://wiki.diyfaq.org.uk/index.php?title=Mains_Voltage
(Can't remember, but did the proposed shift to mains spec +/- 10% ever happen? I have a feeling not, but am not sure)
--
Cheers,

John.

/=================================================================\
  Click to see the full signature.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
John Rumm wrote:

I think that is the spec, but in reality its maintained a lot closer than that.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Useful and interesting (as ever) stuff.
A few tiny comments from a layman:
Extra Low Voltage Add to the heading "or ELV" for consistency with the preceding "Low Voltage or LV"
Live You will probably already have spotted the typo in line 1 of "wore" for "wire".
Why is Neutral a Live wire? In penultimate line similarly a typo of "(this" for "(This"
+/- 10%
I couldn't find anything which replaces the +10/-6%. And the guys at http://www.voltageoptimisation.com/ state that "In the UK, the statutory supply limits have not yet been fully harmonised, with a somewhat tighter tolerance still in force: 230V +10%/-6% (216-253 Volts).
Background to the change to 230V
Any value in adding at the end something like:
"In 1994 the legislation governing the supply of electricity[1] was amended to require 230 volts rather than 240 volts between the phase and neutral conductors; but at the same time it allowed supply at 10% above (rather than 6 %) or 6% below. The net effect was that (within rounding) suppliers didn't have to change their practice.
The legislation in 1994 was the first stage in harmonising voltages across the EU."
[1] The Electricity Supply Regulations 1988 S.I. 1988/1057
--
Robin
PM may be sent to rbw0hotmailcom
  Click to see the full signature.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
On 04/07/2010 18:00, Robin wrote:

Thanks for those...

Yup, our main FAQ still contains the prediction of a change to +/- 10% for Jan 2003. Probably about time that went ;-)
http://www.diyfaq.org.uk/electrical/electrical.html#240V
--
Cheers,

John.

/=================================================================\
  Click to see the full signature.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Yes, we wrote that before 2003 ;-)
It got postponed a couple of times as various CENELEC countries were not able to meet it. Last I heard, it was now up to each country to decide when to change, and no longer CENELEC (or EU) wide. I got the impression there wasn't anything much in the way of any push behind it anymore.
--
Andrew Gabriel
[email address is not usable -- followup in the newsgroup]
  Click to see the full signature.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Sorry. I should have known you would have been there, done that.........
In penance (and/or 'cos I'm sad) I've checked with DECC the current position on +/- 10%. They pointed me to http://www.decc.gov.uk/en/content/cms/what_we_do/uk_supply/resilience/gas_electric/electricity/electricity.aspx which states "At present in Great Britain, domestic supply must be within the voltage range of 216-253 volts, which is +10/-6 percent of 230 volts. This is set to change within the next year to 230 volts +/- 10 percent, as this fits in with voltage standards across the rest of Europe."
I am sure the fact I was reminded of "and they'll be free beer tomorrow" was purely down to my imagination.
--
Robin
PM may be sent to rbw0hotmailcom
  Click to see the full signature.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Who was going to be free beer?
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

LOL!
Themm es wot (i) cant' conttrol ther diggits, (ii) cantt chekk there tie-pin, and (iii) dough-not its Scilly too send wenn dwinking before luncheon?
(And in any event, do I get time off for having discovered before lunch that my car was nicked overnight?)
--
Robin
PM may be sent to rbw0hotmailcom
  Click to see the full signature.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
"John Rumm" wrote...

I would guess (educated guess!) because it can be pulled to a potential other than the local earth if there's a transformer / substation fault? I've certainly seen unsafe voltages ( > 100V) on neutral lines when things have gone Very Wrong with the local substation, even an abnormal load on one phase can pull the SS neutral to quite a high voltage and coupled with an earth fault at the SS this can result in PME earths at relatively high voltages compared to a true earth - I've measured 240V between a sink and its wastepipe once or twice!
Dave H.
--
(The engineer formerly known as Homeless)

"Rules are for the obedience of fools, and the guidance of wise men" -
  Click to see the full signature.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Robin wrote:

Indeed. Well done that man/men.

And another :-)

Very few people are aware that the switch live in a light fitting is live. If it was marked they wouldn't know what it meant - and they frequently aren't marked anyway.
Is it worth adding that? Or does it belong elsewhere?
--
Dave - The Medway Handyman
www.medwayhandyman.co.uk
  Click to see the full signature.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Any mention of sleeving needs to come with a big cavet that it's so often fitted incorrectly on professional installs, that no reliance should be placed upon any sleeving found in an installation.
TBH, it would be better if it wasn't fitted in the first place, but that's too obvious to an inspector, whereas fitting it in all the wrong places isn't.
--
Andrew Gabriel
[email address is not usable -- followup in the newsgroup]
  Click to see the full signature.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
On 05/07/2010 20:44, The Medway Handyman wrote:

It is worth mentioning, but probably elsewhere. The "neutral" (i.e. black/blue) wire in a light fitting coming from the switch is a switched line and not actually a neutral at all. While what the article is talking about is why a genuine neutral (of whatever colour) is also technically speaking a live wire!
--
Cheers,

John.

/=================================================================\
  Click to see the full signature.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
John Rumm wrote:

Good one John.
Suggested changes:
Reduced low voltage system
A system in which the nominal phase to phase voltage does not exceed 110 volts and the nominal phase to earth voltage does not exceed 63.5 volts.
This is a system you will frequently find on building sites for supply to (110V rated) portable power tools and lighting equipment. Site supplies are characterised by the use of yellow-coloured industrial plugs, cable and transformers.
==== Why is Neutral a Live wire?
Neutral is considered a "live" wire because under normal conditions, a current flows in the neutral wire. You may consider the earth wire "dead" in comparison because under normal conditions, no current (or an extremely small amount) flows in the earth wire.
Consequently, although the neutral is bonded to earth at the electricity substation (and is usually therefore benign) it is possible under certain circumstances to get an electric shock by touching a neutral. Conversely, unless there is a very significant (and dangerous) fault in an installation which effectively makes the earth wire "live", you should never get an electric shock from touching an earth.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
On 05/07/2010 11:49, Dave Osborne wrote:

ok added.

Was this a suggested replacement for the whole section or an addition to it?

--
Cheers,

John.

/=================================================================\
  Click to see the full signature.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
John Rumm wrote:

Er, a replacement actually. TBH, I thought your original was too wordy, too complex an argument and out of character with the style of rest of the article. IMHO you just need a simple and straightforward rationale for the use of the word "live".
Cheers, DaveyOz
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Dave Osborne wrote:

Just read this back. Sorry if it sounds harsh; I'm in a bullish mood this morning :-)
DaveyOz
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
On 05/07/2010 13:04, Dave Osborne wrote:

Tis ok, no offence taken ;-)
I quite liked your words, but thought of using them as an intro to (some of) my original ones!
One point I felt worth making was that while the shock risk from elevated neutral voltage was small, the current leakage to earth on a short could be substantial. This potentially has knock on effects with regard conductor heating / damage (particularly with the typically smaller protective conductors)
--
Cheers,

John.

/=================================================================\
  Click to see the full signature.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
John Rumm wrote:

Sure, but shirley these are subtle points more suited to a different, more in-depth article?
I see this particular article as an easily digestible "next step up from a dictionary definition" and wouldn't want the non-technical reader to be bogged down in too much detail. However, it's your article, so go for your life!
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
On 05/07/2010 17:19, Dave Osborne wrote:

ok, have a look now - went for something between the two. ;-)
--
Cheers,

John.

/=================================================================\
  Click to see the full signature.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
John Rumm wrote: <snip>

Cool.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

HomeOwnersHub.com is a website for homeowners and building and maintenance pros. It is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.