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Post by OziRiS on Feb 8, 2016 13:10:30 GMT
Time to create a thread for discussing various topics on electricity, maybe? You guys have been at this for 5 pages now. Just saying... Are you venting? Not really, no  I'm just saying it seems there's enough interest in the subject that it should have its own thread, instead of letting it take over this one. |
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Post by kharnynb on Feb 8, 2016 13:12:42 GMT
Correction, as c64 said, Finland also uses 20k volt, not 7k.
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Post by kharnynb on Feb 8, 2016 13:14:12 GMT
Time to create a thread for discussing various topics on electricity, maybe? You guys have been at this for 5 pages now. Just saying... Getting sparkies started... Oops  ? |
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Post by the light works on Feb 8, 2016 15:09:39 GMT
7KV is just local transmission. I believe it steps up to around 10 KV, then 41KV, then high voltage for regional distribution.
here, a padmount 3 phase transformer will be a single core, but a pole top set will be separate cans.
and as I said, for residential use, where we don't need large motors, 3 phase takes twice as many wires to transport, yet with a center tapped transformer, can deliver two voltages and a higher total amperage on three wires into the house.
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Post by the light works on Feb 8, 2016 15:10:06 GMT
so you guys run one-phase distribution - as differentiated from single phase. your transformers step the 480V distribution to 240V for residential taps. here, they step 7000V down to a three wire tap that has 240V line to line and 120V line to neutral. a three phase service has 4 wire taps, which are either 480V or 208V line to line and correspondingly 277V or 120V line to neutral. Now I see the confusin'.... Right, we get three plus one (neutral) wires down the road from local transformers, one wire to neutral up each smaller street as a single phase 240v, the other "all three" combine to three phase 480v. Our supply is the same as yours but at twice the voltage, as you explain it, but in our "flavour", 480 line to line, 240 line to neutral. Thats all we get, we dont get the "In-between" taps you have. One other thing, we have overhead high voltage national network to local transformers, but, the overhead local wires to local on the pole transformers are not that usual any more, local substations go underground to local supply. actually, you have ONLY the in-between tap. |
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Post by Lokifan on Feb 8, 2016 16:50:40 GMT
The place where all things sparky goes.
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Post by the light works on Feb 8, 2016 17:06:56 GMT
the interior of a US breaker panel. Attachment Deletedthe small one next to it is the communications distribution panel. |
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Post by GTCGreg on Feb 8, 2016 17:35:27 GMT
the interior of a US breaker panel. View Attachmentthe small one next to it is the communications distribution panel. Add two circuits? No problem. There - I fixed it! |
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Post by kharnynb on Feb 8, 2016 20:45:32 GMT
finnish style residential breaker box, before adding the cover:
top: thermstat for floor heating, ground fault box, 3 way and 5x one way.
middle, 3 16 amp breakers for kitchen sockets, dishwasher and "cold alley", then 9 10 amps for wall sockets and lighting runs around the house.
Bottom: 3x 16 amp stovetop, 3x 16 amp saunastove, 3 x 16 amp outdoor equipment, includes 2 car heater sockets. 3 x 16 amp heating.
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Post by GTCGreg on Feb 8, 2016 22:19:05 GMT
finnish style residential breaker box, before adding the cover: top: thermstat for floor heating, ground fault box, 3 way and 5x one way. middle, 3 16 amp breakers for kitchen sockets, dishwasher and "cold alley", then 9 10 amps for wall sockets and lighting runs around the house. Bottom: 3x 16 amp stovetop, 3x 16 amp saunastove, 3 x 16 amp outdoor equipment, includes 2 car heater sockets. 3 x 16 amp heating. I assume the big breaker on the lower left is the main and all the black wires are feeding the breakers? The blues are neutrals? The breakers in our panels are fed by buss bars that the breakers lock into. It's a lot simpler that way and eliminates all those connections that can go bad. It makes it real easy if you have to change or add a breaker. All you do is disconnect the load wire and pull out the old breaker and slide in the new one. You can even do it with the power hot if you're careful.  |
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Post by wvengineer on Feb 9, 2016 1:04:47 GMT
finnish style residential breaker box, before adding the cover: top: thermstat for floor heating, ground fault box, 3 way and 5x one way. middle, 3 16 amp breakers for kitchen sockets, dishwasher and "cold alley", then 9 10 amps for wall sockets and lighting runs around the house. Bottom: 3x 16 amp stovetop, 3x 16 amp saunastove, 3 x 16 amp outdoor equipment, includes 2 car heater sockets. 3 x 16 amp heating. What is the total current rating for that box? To me, it looks like you have say #10 wire feeding each breaker in parallel. That would only give the box 30 amps for each phase before you risk overloading the wire that feeds each breaker. Greg Posted normal residential panels. For reference, here is what a 3P panel looks like. They still use indiviusal buses for each phase and the breaker will connect to each phase. Smaller setups will clamp the buss bar, but higher power ones usually will have each phase attached by a screw. Attachment Deleted |
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Post by kharnynb on Feb 9, 2016 4:58:50 GMT
that's a 3x 40 amp box, if you look carefully, you can see the main switch(left bottom) has 3 feeds, and 3 wires going out.
the wire is 4mm, or about #5 wire for the feed side, and 2.5mm or about #10 for the pe/n wire and the wires to the groundfault.
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Post by kharnynb on Feb 9, 2016 5:00:26 GMT
these are switching breakers, so you shouldn't need to swap them, unless one burns(that would require an electrician.
on the middle row there is room for about 5 extra breakers.
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Post by the light works on Feb 9, 2016 5:58:51 GMT
the interior of a US breaker panel. View Attachmentthe small one next to it is the communications distribution panel. Add two circuits? No problem. There - I fixed it! the two extension cords were running temporary heaters. |
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Post by the light works on Feb 9, 2016 6:07:22 GMT
these are switching breakers, so you shouldn't need to swap them, unless one burns(that would require an electrician. on the middle row there is room for about 5 extra breakers. you'll note that some of the boxes Greg showed have copper busbars, and some have aluminum. typically a standard panel has a 200 amp bus. one main breaker. - the difference is in an environment like mine, the aluminum bus will corrode and the breaker will no longer make good contact. no good picures - but when that happens, it burns the bus clamp off the breaker and sometimes wipes out neighboring breakers as well. I also occasionally have a terminal go bad on a breaker. Attachment Deleted |
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Post by silverdragon on Feb 9, 2016 9:26:15 GMT
I have never fully trusted Aluminium Buzz bars...
Note I still use the old term of Buzz?...
I have been in big instillations where they earn that nick-name, they do "buzz" with a low hum....
I made sure I had copper in mine when I changed it.
I was offered a "slightly cheaper" one, but I dont need to cut corners like that?.
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Post by GTCGreg on Feb 9, 2016 15:28:21 GMT
Add two circuits? No problem. There - I fixed it! the two extension cords were running temporary heaters. I figured it was something like that. Just poking a little fun. |
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Post by the light works on Feb 9, 2016 15:30:26 GMT
I have never fully trusted Aluminium Buzz bars... Note I still use the old term of Buzz?... I have been in big instillations where they earn that nick-name, they do "buzz" with a low hum.... I made sure I had copper in mine when I changed it. I was offered a "slightly cheaper" one, but I dont need to cut corners like that?. I had one project where the original builder roughed the house in and closed up shop. in a house less than a year old, I had to change out the backplane (busbar assembly) of the panel because it had rotted. |
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Post by kharnynb on Feb 9, 2016 15:48:10 GMT
Here, we don't use aluminium any more in wiring or fuseboxes, not since the 40's anyway (very old houses might have it)
The joke my british electrical engineer friends always used to make is that the UK has the safest plugs, because it has the unsafest wiring systems.
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Post by the light works on Feb 9, 2016 15:59:19 GMT
Here, we don't use aluminium any more in wiring or fuseboxes, not since the 40's anyway (very old houses might have it) The joke my british electrical engineer friends always used to make is that the UK has the safest plugs, because it has the unsafest wiring systems. we allowed aluminum wiring for a short time in the 60s or 70s in mobile homes as a cost saver. my standing advice for those is to get out as soon as possible. it is allowed to be used for circuits 30 amps and above, if the device terminals are rated for it - but since it is required to be larger than copper wire, it is usually more expensive to use than copper, which means only a few die hard fans of it still use it. the only place aluminum is still commonly used as a conductor is for the service entrance wiring - and in cheaply built houses, the main breaker bus. |
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