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Joined: Feb 2003
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i can understand the european system and far for north american system most home are wired for 120/240 volts ( most common ) and some case 120/208 volts also but in commercal and industrail system go much higher we have 277/480 volts system and all the panel boards are marked clear for waring the high voltages and genrally take a extra step more with 277/480 system and if you want to know if i got wire zapped with it and yeah it do pretty messy with 480 v it can do some damge fast if you dont look out but i am not sure what you guy do at U.K. and N.Z. system do but i do remeber french system very well it is very simuair to U.K. system .
for flash over on higher voltage it is very simuaur with 400/415 volts you guys metion
merci marc
Pas de problme,il marche n'est-ce pas?"(No problem, it works doesn't it?)
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Joined: Jul 2002
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Gidday Marc, You mention 277/480VAC, where is this used, if I may ask a question?. With regard to "Flashover", this term is really only used with HV(1000V+)systems as the voltage only jumps between phases over this voltage. With respect to an arc-flash, however(this is what happens when 2 phases or a phase and Neutral) hit one another, wether it be because of wind or a screw-driver of a person wiring a Panel, the results are not the same. Hope this helps.
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thanks trumpy :
now i get your picture about flashover but some case we do get flashover even in very high humity conditons but not the same as "bolt falut" ( driect short) the last time i see the flash over was few week ago i was working on breaker and the humity was sooo high in one room like steam vapor it was pretty spooky when i see alot of mositure on the wall i say to myself "oh oh merde( a famous four letter word i cant print here)!!!" and i can actally hear the electic crackle (noise) and smell it then turn off the main power source at the main breaker with insluated gloves and hot stick to push breaker off and check the damage and alot of sweat on wire can flashover btw this is a big 480 volts 4500 amp switchborad!! that was amazing to see the flashover for this size and lucky did not blew up
thanks for explain trumpy
ps some very high voltage system can flash over with power surge too
Pas de problme,il marche n'est-ce pas?"(No problem, it works doesn't it?)
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Joined: Feb 2003
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opps i forgot to add this one the 277/480 volts are common on commercal and industrail systems but never for homes for safty reason
sorry about that
merci marc
Pas de problme,il marche n'est-ce pas?"(No problem, it works doesn't it?)
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Joined: Jul 2002
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Marc, No worries, that's what I'm here for. I can't believe that the humidity gets that bad where you are, is this true?. So you use Hot-sticks and gloves, too!, join the club. However, I am required to use them on 3.3kV,6.6kV,11kV,22kV and 33kV, for isolation and re-energising procedures. Whopping great gloves and big Fibreglass telescopic Hot-sticks, the Higher voltages,22 and 33kV, give me the willies, when I am working with them!.
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Joined: Aug 2001
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Trumpy, Commercial power in the U.K., N.Z. etc. is all pretty standardized on 230/400V (or thereabouts) wye systems.
If you look back through tha threads though, you'll see that America has a multitude of systems that have been installed for commercial power. In addition to 120/208 and 277/480 wye systems, there are 240V delta, 480V delta, and the strange (from a non-U.S. perspective) 4-wire delta arrangement.
Canada has 347/600V wye as well, although I'm not sure how extensively it is used. (And I wonder whether these systems were derived from older 600V delta supplies?) Maybe one of our members from the Great White North could add some details.
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Joined: May 2002
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Paul,
I am so happy being only dependant on two sets of incoming supplies to our buildings over here,
good old 230v ac 100amp for (most) domestic services.
and 400 v ac three phase (minimum) 100 amp per phase for commercial/small industrial service supplies.
I do find, on some of the larger contracts that i work on are in excess of 600a per phase on three phase, but the voltage is the same, and also on some larger domestic properties we have two phases comming in and sometimes three, depemdant on the load requirements,
The company is currently (sorry about the pun) working on a supply incomer of over 1000Amp per phase, this is going to be a fun installation to complete !!
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Joined: Feb 2003
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trumpy: the switchboard was located next to the boiler room and it was seprated by 1/2 meter thick cement wall and hevey fire door and i found where the hevey moisture came from it came thru the floor drain when the boiler go thru "blow down " and blew the steam up the floor grates and got too much condation when the electrical room exhaust fan cant remove all the vapor and that when the troble started grrrrrrrr i hate it and i did take no chance i knew that industal companie so i grab my hot stick and insluated gloves and trip the breaker manually it was hard one to trip but i got it and clean the concat and "charge springs" i mention that to my clinet that should use fuse insted of bloody expensive breaker it cost over 8.000 dollars for a piece of crap ( 8thousand dollars not a mistype) and it is my simple rule anytime want to fool around with 480 and higher just get hotstick and gloves and yes it is mantory for me work on meduim voltage system too 4160votls is most common i deal with it but i go higher as 15 kv as need the last highest one was 69 kv !!! that is spooky with that one merci marc
Pas de problme,il marche n'est-ce pas?"(No problem, it works doesn't it?)
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