Discuss Anyone have American electric questions? in the USA Electrical Forum area at ElectriciansForums.net
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??
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.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....
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.
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
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.
Correct! Which is why the customer many times calls for ground rings in their installations. The NEC sets minimum standards only.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...
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, cheersthe 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.
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 ]
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 ]
my experience is most electronics is DC internally, am i wrong???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 think
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.
my experience is most electronics is DC internally, am i wrong???
Ok I checked out with a couple of electricians lets say more estute than me, and low and behold, as they have never worked on US type of equipmemt before there quite apprehensive touching this, even after I explained what your solutions were; i have another person to speak with, but in the event, iv'e come up with plan B, that iswhen 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.
cheers for getting back on this..blinding stuff, one thing my voltage is 250W, not 700W as I thought, so i got a 500W voltage convertor...maybe on to the right thing afterall, cheersi agree, the step down transformer is a good solution, and you are correct that
the internals of your system will only see DC anyway, so 50 or 60 hz in the wall voltage is irrellevant. good solution
Well, doesnt 17th ed require you to de-rate the ampacity of the wires used if there is more than 3 current carrying conductors? In the NEC if you have - for ex. - 10 wires in a raceway [conduit or trunking] the ampacity of the wires is de-rated 50%.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???
single pole switch $1 or $2, two way switch $5-8 each.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
Well, doesnt 17th ed require you to de-rate the ampacity of the wires used if there is more than 3 current carrying conductors? In the NEC if you have - for ex. - 10 wires in a raceway [conduit or trunking] the ampacity of the wires is de-rated 50%.
single pole switch $1 or $2, two way switch $5-8 each.
Reply to Anyone have American electric questions? in the USA Electrical Forum area at ElectriciansForums.net
We get it, advertisements are annoying!
Sure, ad-blocking software does a great job at blocking ads, but it also blocks useful features of our website. For the best site experience please disable your AdBlocker.