Is it a regular occurance, that an Electrician in the UK, would come into contact with 415V, Phase-Phase-Phase?. We use over here, 400V, between all phases, but, what I would like to ask, is, is your technique, any different from working on 230 to Earth, with the risk of inter-Phase Flash-over?. Your thoughts please-
I deal with three phase ( red phase 230v, yellow phase 230v, blue phase 230v )on a day to day basis.
I have only had one flashover between phases and that was not pleasant, it was caused by my then apprentice bringing in the wrong isolator (he was a third year, so in theory he should have known his a b c).
Working on three phase (415 or it is now known 440 or 400v ) is you would use the same caution and respect that you would for 230v single phase.
about one of the only things i have noticed within the time i have been an electrician is that the bonding of the enclosures are a lot better than ordinary single phase panel boards.
if there is anything else you want to know, just ask.
Re: 415V ?#136231 03/23/0307:31 AM03/23/0307:31 AM
that an Electrician in the UK, would come into contact with 415V, Phase-Phase-Phase
Well, I hope you don't mean "in contact" literally!
I mostly deal with residential, which as you know is single phase 240V here. I work with 240/415V 3-ph systems in some small commercial jobs, although these places generally have only 1-ph 240V loads, so there are no 415V circuits beyond the distribution panel. There is, of course, the very real chance that different phases have been brought into close proximity, or even into the same switch box. I've seen some DIY botch-jobs that have left a twin light switch liie this, and I wonder whether the person who "threw" those wires into rthe box realized that he was dealing with 415V between them.
Do you regularly used fused test probes in NZ when taking voltage measurements, to minimize the risk of an explosive arc if the meter was, say, set on a current range by mistake?
we dont actually come into contact, ouch ! (i have only once, and it cost me a lot of time off)
We are sometimes called into a lot of commercial properties to fix lights and the such like and most of the time the identification of circuits and phases is not done, so you end up removing the plates from switch gear and finding a bunch of red cables and the theory should be that that set up is red phase 230v. then when you start testing you get two different phases and sometimes three.
There are requiremnts within the regulations over here to identify each circuit and to what breaker it is fed and from what phase,
IE R1/DB3/LT1 Red phase / Distribution Board 1 / LighT number 1.
if the R changes to Y or B you automatically know you have three phase within, (also by the warning notice, Danger 415 Between Switches, that should also be placed on or about the switch gear.
Get real, what are the 415V going to do to you? Jump out of the switch and bite you? Geez, those British volts must be something out of the ordinary!
Proper identification of the circuits is a really good thing. Are the circuits in England identified in real life or just in the regulations? It's all too often neglected in Sweden. (New offices are good, old homes a disaster) Even experienced electricians sometimes miss that single pole breakers or diazed fuses in fact form a 3-phase group. The diazed panels are a real danger, in my humble opionion: There are three rows of fuses in the box, corresponding to the three phase busses. A poly-phase block consist of two or three fuses in a column. If there is a circuit number above the top fuse only, it tells you that it's a 3-phase circuit. The trouble begins when the box is orginally used (or identified) for single-phase circuits with a number above each fuse, but later 3-phase circuits are added.
All of a sudden the list next to the box goes:
1.) Lights, first floor 2.) Sockets, first floor 3.) Kitchen sockets, 3-phase 4.) Sockets second floor 5.) Disused 6.) Dishwasher, 3-phase 7.) Garage 8.) Basement 9.) Fridge, 3-phase
Not everybody is kind enough to write 3-phase after #3, 6 and 9... Worse, the list often gets lost. I've even seen a panel where either the list was wrong or a 3-phase block actually zig-zaged in the panel.
[This message has been edited by C-H (edited 03-23-2003).]
The warning notices go along with my comments elsewhere about the IEE's views on anything over 250V.
If you go into a restroom here and it has two or more hot-air hand dryers, then you may well see a similar sign "Danger: 415V between" with arrows. That's a requirement if the dryers are on different phases and within arms reach of each other.
John, The identification of circuits is often sadly lacking in the residential and small commercial environments in which I work. I often spend the first hour just tracing which fuse/MCB feeds what.
I did once see a medium sized shop, full of freezers, lighted display cabinets, and so on, in which somebody had painted the fronts of the sockets red, yellow, and blue!
Paul, To answer you question, regarding Fused Test leads, I've used them since I first started in this Electrical game, makes sense, doesn't it?. But, it is really only Industrial Tech's,Faultsmen and the odd Sparkie that is in the know, that use these Leads, over here. I have 1000V, 500mA, leads myself, how about you?.
After doing some fatal damage to a rather nice piece of test equipment when i was an appretice (many years ago) ALL my test leads are fused at 500mA,
In regarg to signage i have to agree will Paul,
most of the time in large commercial / industrial you will find the signage is usually there, but sometimes (ok most of the time) another sparky has come in and done a bit here and a bit there, added an otlet there, taken a supply from hear, wired another piece of equipment from another supply and low and behold what is written in the panel is not what is installed in the building !!
As we specialise within the liesure industry, Bars, nightclubs etc, they are the worst !!
its like ` lets see who can do this the cheapest` and when it goes wrong, then they call the proffessionals in!!
C H, if 415 jumped out at me, i think i should have to go and seek proffessional advice from my local shrink !!!
But on another topic, slightly, i have had a 100a Three Phase isolator explode at me, we contacted the manufucturer and they said it was a design fault !! took a few years of me i can tell you. !