- Thread starter 1capybara
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E
Engineer54
Everyone on this forum has been great in answering all my 17th ed questions,
pls lmk if u have any NEC [American electric] questions, I will be happy to answer
What electrical testing is required, on a newly completed domestic installation according to your NEC code requirements??
M
malcolmsanford
Get the journeyman to switch it on, with you a safe distance away .........
it depends on the inspector, most common is a ground rod test with a 3 pin tester, and test with a "megger" [mega-ohm meter] phase to phase,
phase to neutral, and phase to ground and neutral to ground for feeders only, not for the branch circuits. and voltage test everything. none of this is required by NEC. here our work is inspected by 3 different agencies who apply rules which are sometimes above and beyond the NEC, which is their right
as the AJD [authority having jurisdiction].
phase to neutral, and phase to ground and neutral to ground for feeders only, not for the branch circuits. and voltage test everything. none of this is required by NEC. here our work is inspected by 3 different agencies who apply rules which are sometimes above and beyond the NEC, which is their right
as the AJD [authority having jurisdiction].
Watched a program called Holme on Homes based in Canada and the electrician fitted a GFI(RCD) and said it should be tested every month not 3 as in this country.
E
Engineer54
As far as i can remember... in households, they are only required for outdoor receptacles and bathroom receptacles, i could be wrong there, but not too far out!!! They certainly don't make use of RCD devices as we do in Europe. Tripping value is 6mA, and mainly incorporated in the receptacle outlets, although some circuits will be supplied by RCBO type breakers in the enormous DB panels....
the trip setting on our gfci outlets is 5mA designed to be below the lethal shock level. Us Yanks dont see the advantage of a trip level of 30 or 300mA which would allow a lethal shock without tripping.
The new thing here is AFCI [arc fault circuit interrupters] designed to prevent fires due to sparking.
BTW, im from California, but have been working in the Mid East for 3 years where im learning 17th ed. The difficultest part is the terminology is different for every little thing.
E
Engineer54
That's funny, ...every US GFI breaker or GFI receptacle i've come across, and that a considerable amount, have always been clearly marked for 6mA!!!
Haha... we have a range of RCD devices, some come in an S type version, (time delayed) 10mA, 30mA, 100mA, 300mA, 500mA
We in Europe tend to protect complete circuits with RCDs, whereas accross the pond there, you tend to protect a load/appliance via a RCD receptacle, or a GFI breaker circuit with a specific single load. Imagine the level of nuisance tripping on for argument's sake, a receptacle circuit with an RCD breaker trip level of just 6mA!! lol!!
Also we ensure that installations are limited to having a maximum touch voltage of 50 volts, so that they are not lethal. ...lol!!! The easiest way of explaining that to you, is maximum values of ground rod protected systems linked to RCD devices. (As the states use a hell of a lot of TT systems ''Ground rod grounding'') So U =RI, say R=50v/0.3A (300mA) =167 ohm Max, ....or R=50v/0.1A (100mA) =500 ohms Max. I'll let you do the calc for a 30mA RCD...lol!!
Hope that makes some sense to you, as i'm not concentrating to well, ... i'm doing other things at the same time here at the moment...lol!!!
Haha... we have a range of RCD devices, some come in an S type version, (time delayed) 10mA, 30mA, 100mA, 300mA, 500mA
We in Europe tend to protect complete circuits with RCDs, whereas accross the pond there, you tend to protect a load/appliance via a RCD receptacle, or a GFI breaker circuit with a specific single load. Imagine the level of nuisance tripping on for argument's sake, a receptacle circuit with an RCD breaker trip level of just 6mA!! lol!!
Also we ensure that installations are limited to having a maximum touch voltage of 50 volts, so that they are not lethal. ...lol!!! The easiest way of explaining that to you, is maximum values of ground rod protected systems linked to RCD devices. (As the states use a hell of a lot of TT systems ''Ground rod grounding'') So U =RI, say R=50v/0.3A (300mA) =167 ohm Max, ....or R=50v/0.1A (100mA) =500 ohms Max. I'll let you do the calc for a 30mA RCD...lol!!
Hope that makes some sense to you, as i'm not concentrating to well, ... i'm doing other things at the same time here at the moment...lol!!!
yes, we mostly use what you call TT systems. think about this: A= v/ohms. for 120v and maximum allowable ground of 25 ohms, 5 amps flow and the 20 amp breaker wont trip.
But the 5 or 6 mA gfci will, so lethal shock is prevented. in a British system, 30mA RCD, you would be dead.
But the 5 or 6 mA gfci will, so lethal shock is prevented. in a British system, 30mA RCD, you would be dead.
Yes, an electrician was a decent tradesman job in the States. But now with the global depression, our salary is only 50-60%
what it used to be, and thats if you can get work. Unemployment is sky high, especially in construction. I get an email from ppl I used to work with saying "Im not working and I dont know anyone who is." Which explains why I work in the mid-east, there is no work in the States. Hopefully, when normal economic times return, electricians will go back to getting decent wages like we always used to
what it used to be, and thats if you can get work. Unemployment is sky high, especially in construction. I get an email from ppl I used to work with saying "Im not working and I dont know anyone who is." Which explains why I work in the mid-east, there is no work in the States. Hopefully, when normal economic times return, electricians will go back to getting decent wages like we always used to
C
chris N.I
How's it goin lads,don't use this forum much,this is my first thread.Gona start using it much more now.Anyway,Im a spark from N.I looking for work in either Afghan or USA.I was told that a British certified electrician would not be recognised in USA,and that I would have to apply for an apprentice journeyman's state licence,taking up another 4 years! Is this true?
This info was given to me by a fellow user on Flour corp's logcap forum,who is himself a (USA) journeyman working in Afghanistan.I found it hard to believe,I expected an update course of some discription.
Any opinions or info would be appreciated.cheers lads
This info was given to me by a fellow user on Flour corp's logcap forum,who is himself a (USA) journeyman working in Afghanistan.I found it hard to believe,I expected an update course of some discription.
Any opinions or info would be appreciated.cheers lads
licensing in the states is in control of each individual state, and each states sets its own rules. you just have to check with the state u want 2 go to. btw, theres lots of UK electricians working in Afghanistan, Iraq, etc. Your 17th ed license is the only thing u need in
British bases, Afghan Army or Police bases, etc.
British bases, Afghan Army or Police bases, etc.
E
Engineer54
Where do you keep getting this ''lethal'' shock thing from?? 30 mA is the threshold of heart fibrillation!!! It's not just the UK that use this level in RCD device (GFI) protection, the whole of Europe uses it too, along with most of the Middle and Far East. Coming back to the UK/Europe for a moment, we also have very stringent disconnection times for different levels of leakage current that may pass through an RCD, that all RCD devices MUST meet.
If you were even partly correct in your idea of ''30 mA and your dead'' theory, we could be talking about millions of casualties, ....but alas as your so wrong, there isn't and never has been!!! Maybe talking to a UK or European electrician where your working in the Middle East can explain more about our RCD regulations along with the 50 volt touch voltage limitations many of our circuits must also comply too...
Your NEC doesn't call for, or state a ''maximum'' rod Ra of 25 ohms. It notes a stated recommended value, and if that value cannot be obtained with a single rod then another rod must be provided. Your not even required to test the second rod, or the combined value, as according to the NEC, providing the second rod fulfills obligations...
Correct! Which is why the customer many times calls for ground rings in their installations. The NEC sets minimum standards only.
Our inspectors [my installs are inspected by 3 organizations] set their own spec over and above the NEC minimums. Engineer54, thx for your posts, I always learn from them
E
Engineer54
Very similar to our UK Reg's in many respects, ours too are minimum requirements, although there are some that treat it as a bible, that cannot be deviated from. I'm often accused of applying my own rules, i'm not, there often requirements that are made in electrical specifications to contracts, which are always of a higher calling than those laid out in our Reg's.
I must say, that the NEC code requirement for minimum Rod Ra values make much more sense than ours. Whereas yours call for 25 ohms ours call for 200 ohms!!! Which is why i've never take any notice of that ridiculous figure, and would never leave a TT system at anything like that value ....lol!!!
Having said that, ...i have no time at all for your ''Multi Branch'' circuit arrangement, or the use of screw/wing nut connections, seen far too many catastrophic failures of those things, and some of them are bloody huge things!!! ...lol!! Anyway it's good to hear you take an interest in our Reg's (BS7671), it's always good to broaden your outlook, and you just never know, ...it may well come in very useful later for you.
Are you working overseas for an American company to US codes or are you working with various codes, as i often find myself doing??
I must say, that the NEC code requirement for minimum Rod Ra values make much more sense than ours. Whereas yours call for 25 ohms ours call for 200 ohms!!! Which is why i've never take any notice of that ridiculous figure, and would never leave a TT system at anything like that value ....lol!!!
Having said that, ...i have no time at all for your ''Multi Branch'' circuit arrangement, or the use of screw/wing nut connections, seen far too many catastrophic failures of those things, and some of them are bloody huge things!!! ...lol!! Anyway it's good to hear you take an interest in our Reg's (BS7671), it's always good to broaden your outlook, and you just never know, ...it may well come in very useful later for you.
Are you working overseas for an American company to US codes or are you working with various codes, as i often find myself doing??
I work on British Camp Bastion and Afghan camp Shorabak, both to 17th ed., American Camp Leatherneck to NEC, and private jobs to
no spec other than "make it safe."
"multi-wire branch circuit" is just shared neutral. A perfectly balanced shared neutral
carries no load. so thats safe.
a ring circuit on the other hand........
no spec other than "make it safe."
"multi-wire branch circuit" is just shared neutral. A perfectly balanced shared neutral
carries no load. so thats safe.
a ring circuit on the other hand........
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Engineer54
Always good to talk/banter with you 1capybara...
How are you getting on with the multitude of testing that the 17th ed calls for??
....Haha, come on, when have you ever seen a perfectly balanced multi branch circuit in a domestic or commercial setting, with mixed lighting and receptacle loads, ...that is almost an impossibility?? Oh, and if you have a break in the neutral conductor at the DB??
OK then, so let's hear your concerns with the UK 13A ring final circuit??
How are you getting on with the multitude of testing that the 17th ed calls for??
....Haha, come on, when have you ever seen a perfectly balanced multi branch circuit in a domestic or commercial setting, with mixed lighting and receptacle loads, ...that is almost an impossibility?? Oh, and if you have a break in the neutral conductor at the DB??
OK then, so let's hear your concerns with the UK 13A ring final circuit??
About those shared neutrals, any two circuits [of equal value and different phases]
sharing a neutral will reduce the neutral load, not increase it, right?
1. if your not aware it is a ring circuit, you disconnect the wire on what you believe is the "line" side, you now assume the
outlet is dead. but it isnt because its also fed from what you thought was the "load" side.
2. the homeowner has a blown fuse in the BS1363 outlet, so he bypasses the fuse. now you have an outlet designed for
13A but its capable of 32A before tripping a breaker.
sharing a neutral will reduce the neutral load, not increase it, right?
1. if your not aware it is a ring circuit, you disconnect the wire on what you believe is the "line" side, you now assume the
outlet is dead. but it isnt because its also fed from what you thought was the "load" side.
2. the homeowner has a blown fuse in the BS1363 outlet, so he bypasses the fuse. now you have an outlet designed for
13A but its capable of 32A before tripping a breaker.
E
Engineer54
Capy,
Sorry for the delay, been a very busy week for me!!!
That's the point, the (multi branch) circuits have to be finely balanced to have no load on that neutral conductor, and your not going to find many of those in a domestic/commercial environment, when mixing lighting and receptacle circuits, .... now are you???
1/ One would hope that the protective device (MCB) would have been switched to the off position before disconnecting the wiring at any socket outlet device!! And seeing as you would be switching the MBC off, you would hopefully have also noticed at the time, that it is rated at 30/32A...Yes??
2/ The same thing can be said of any fuse, .....they can all be defeated, in one way or another. The fuse is there for a purpose, if a bloody idiot wants to defeat that purpose, ..... Well you just can't protect idiots from themselves, can you?? Does that make, what is a pretty safe all round circuit, ...unsafe?? We also use the same fused plug top for 16A/20A radial circuits, are they also unsafe??
Sorry for the delay, been a very busy week for me!!!
That's the point, the (multi branch) circuits have to be finely balanced to have no load on that neutral conductor, and your not going to find many of those in a domestic/commercial environment, when mixing lighting and receptacle circuits, .... now are you???
1/ One would hope that the protective device (MCB) would have been switched to the off position before disconnecting the wiring at any socket outlet device!! And seeing as you would be switching the MBC off, you would hopefully have also noticed at the time, that it is rated at 30/32A...Yes??
2/ The same thing can be said of any fuse, .....they can all be defeated, in one way or another. The fuse is there for a purpose, if a bloody idiot wants to defeat that purpose, ..... Well you just can't protect idiots from themselves, can you?? Does that make, what is a pretty safe all round circuit, ...unsafe?? We also use the same fused plug top for 16A/20A radial circuits, are they also unsafe??
yes, its state by state, if u have 4 years experience as an apprentice, your eligible to take the
licensing exam in any state [afaik!], then once your licensed in one state, other states [but not all other states]
have reciprocal licensing agreements with their neighboring states. i cant compare that to the UK, dont u have
4 years apprenticeships also?
licensing exam in any state [afaik!], then once your licensed in one state, other states [but not all other states]
have reciprocal licensing agreements with their neighboring states. i cant compare that to the UK, dont u have
4 years apprenticeships also?
M
MCACelectrical
Hi
Apprenticeships are about 3-4 years i'm pretty sure, i think after you've done the 4th year which would be entirely work based, they let you get on with it.
everyone does it slightly different here, i'm not a major fan of the JTL scheme. Although i can see how it helps certain people.
Apprenticeships are about 3-4 years i'm pretty sure, i think after you've done the 4th year which would be entirely work based, they let you get on with it.
everyone does it slightly different here, i'm not a major fan of the JTL scheme. Although i can see how it helps certain people.
S
sparkydude
After having just come back from my holiday in florida, a couple of things i wondered if you could help me with .
1. I have noticed that you do not seem to use anything but conduit for commercial installations, the only time i saw trunking used was in disney with lights on it and in small pieces below panels top common up conduit runs. Has nobody thought of introducing trunking to the states as it would seem to be a much quicker way of doing things. instead of 20 runs of tubing you could have one run of trunking???
2. Why dont they like putting 2 way switching systems in hotels/villas, the amount of times i switched the bedroom lamp on at the door switch then off at the lamp and then come the next night go to turn it on and its not going to come on as its off at the Lamp. Stumble across the room to find the lamp and turn it on there. Then repeat every night till I leave .
Nick
1. I have noticed that you do not seem to use anything but conduit for commercial installations, the only time i saw trunking used was in disney with lights on it and in small pieces below panels top common up conduit runs. Has nobody thought of introducing trunking to the states as it would seem to be a much quicker way of doing things. instead of 20 runs of tubing you could have one run of trunking???
2. Why dont they like putting 2 way switching systems in hotels/villas, the amount of times i switched the bedroom lamp on at the door switch then off at the lamp and then come the next night go to turn it on and its not going to come on as its off at the Lamp. Stumble across the room to find the lamp and turn it on there. Then repeat every night till I leave .
Nick
B
breakerman
Hi I dunno if you could help me with this; i bought a sony home theatre sound system amp in US and need use in UK, it's 120v, 60HZ, what can i do in particuler to change the 60Hz to 50HZ, is it poss, i know i have to figure the voltage output to get a rating for suitable transformer, this is where my brain stops working, cheers
on second thought, all electronics are low voltage DC internally after the AC to DC transformer. so if possible, hook a DC power source into the internals of that system, attaching it after the transformer. 3v DC is typical. IMHO. YMMV ["your mileage may vary" as we say in the states ]
]
B
breakerman
cheers, but not quite sure how to hook up, can u expand a bit, might be my way thru, thxon second thought, all electronics are low voltage DC internally after the AC to DC transformer. so if possible, hook a DC power source into the internals of that system, attaching it after the transformer. 3v DC is typical. IMHO. YMMV ["your mileage may vary" as we say in the states
B
breakerman
I think I'm getting the jist of wat your saying, but checkin abvout using a transformer, it seems that if I used a 750w (output max 700w) I woudn't have to be to bothered about the freq, I think that's wat u were intemating in your point, but would that be a safe solution e.g does it damage the machine, I undersand freq fluctuates anyway and most of the AV unit use is AC and not so much DC, wat do u thinkon second thought, all electronics are low voltage DC internally after the AC to DC transformer. so if possible, hook a DC power source into the internals of that system, attaching it after the transformer. 3v DC is typical. IMHO. YMMV ["your mileage may vary" as we say in the states
when u take apart the system, you will find a small transformer attached to the cord where [in a system bought in the states] 120v goes in. in other words, its a 120 VAC to
[typically] 3 VDC transformer. Its two ouputs are 3 VDC and ground. If you have one,
you can replace it with a 230 VAC to [typically] 3 VDC transformer and replace the wall cord [american plug] with a Brit or euro plug.
[typically] 3 VDC transformer. Its two ouputs are 3 VDC and ground. If you have one,
you can replace it with a 230 VAC to [typically] 3 VDC transformer and replace the wall cord [american plug] with a Brit or euro plug.
my experience is most electronics is DC internally, am i wrong???
B
breakerman
This is brilliant, so am I rt in saying it's like converting it to uk system compatible
B
breakerman
I'm goin to double check on this, because I read on an AV furum that with a transformer peaple have been using US amps here no prob, and maintaing it's only really the timer that usees DC!
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