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Author Topic: IEC C14 Madness  (Read 3856 times)

Steve M Smith

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Re: IEC C14 Madness
« Reply #10 on: December 16, 2020, 10:55:11 AM »

I am not the wiring terminology expert but I think I have seen 240 hot legs called L1 and L2, neutral is historically bonded to ground at the panel. Old school 240V wiring may have even included a neutral and a ground.


Is that because your 240v supply is cente tapped neutral to give two 120v supplies? In the UK, the 230v supply is one of three phases in a star formation with a central neutral which is bonded to ground.


Domestic properties get one of the three phases, industrial properties get all three.




Steve.
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Daniel Levi

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Re: IEC C14 Madness
« Reply #11 on: December 16, 2020, 11:43:42 AM »


Is that because your 240v supply is cente tapped neutral to give two 120v supplies? In the UK, the 230v supply is one of three phases in a star formation with a central neutral which is bonded to ground.


Domestic properties get one of the three phases, industrial properties get all three.




Steve.

I believe, despite not being American, that this is in fact the case with 240V being 2x120V one being 180 out of phase compared to the other one, plus unlike our British sockets which are always polarised on the plug/socket side some American 2 prong plugs aren't (similar to Schuko/Italian 3 prong and two prong plugs on the continent.
Note that they can also have 208V on the same outlets in places like apartment blocks and business where the 208V supply is derived from a 3 phase supply and devices are designed to accept either voltage.

Makes our electrical supply seem simple even with our ring final circuits, esp. given the amount of different plugs/sockets they have over there, esp. in the higher power variants. (noting that we have only one common type of domestic outlet with all industrial outlets generally being of the same series of industrial connectors)
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Stephen Swaffer

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Re: IEC C14 Madness
« Reply #12 on: December 16, 2020, 12:58:55 PM »

I believe, despite not being American, that this is in fact the case with 240V being 2x120V one being 180 out of phase compared to the other one, plus unlike our British sockets which are always polarised on the plug/socket side some American 2 prong plugs aren't (similar to Schuko/Italian 3 prong and two prong plugs on the continent.
Note that they can also have 208V on the same outlets in places like apartment blocks and business where the 208V supply is derived from a 3 phase supply and devices are designed to accept either voltage.

Makes our electrical supply seem simple even with our ring final circuits, esp. given the amount of different plugs/sockets they have over there, esp. in the higher power variants. (noting that we have only one common type of domestic outlet with all industrial outlets generally being of the same series of industrial connectors)

This is correct.  Our system does allow a lower voltage to ground-which on the surface would seems to be a little safer.  I am sure there are statistics out there to prove or disprove this-in any case, it really is a moot point given the installed base-changing would be very impractical.  New receptacles are polarized-I would guess that goes back at least 50-60 years given what I see in homes.

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Steve Swaffer

Daniel Levi

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Re: IEC C14 Madness
« Reply #13 on: December 16, 2020, 01:29:03 PM »

This is correct.  Our system does allow a lower voltage to ground-which on the surface would seems to be a little safer.  I am sure there are statistics out there to prove or disprove this-in any case, it really is a moot point given the installed base-changing would be very impractical.  New receptacles are polarized-I would guess that goes back at least 50-60 years given what I see in homes.

One little oddity in Britain is power for worksites, these generally use 110V power (using 16A yellow IEC60309 connectors) supplied by an isolation transformer that is wired to give 55V on both the live and neutral pins, this allows for extra safety as not only are you isolated from the mains but if you come into contact with a conductor then it's only 55V between you and ground (assuming you don't come between both conductors).

The only other plugs in common use are 15A round pin plugs for stage lighting (used primarily due to the lack of a fuse, as a fuse failing up high is a PITA), the smaller 5A and 2A variants for portable/desk lighting either where it is centrally switched or to prevent normal devices being used in said sockets (hotels and university accommodation being common users).

There are also special plugs with T shaped earths for special medical equipment and such like plus Walsall Gauge plugs that were used primarily by users who wanted to stop unauthorised appliances being used, the BBC for example were one such user ad so were London Underground for 110V supplies.

See more here: https://en.wikipedia.org/wiki/AC_power_plugs_and_sockets:_British_and_related_types
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John Roberts {JR}

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Re: IEC C14 Madness
« Reply #14 on: December 16, 2020, 02:19:06 PM »


Is that because your 240v supply is cente tapped neutral to give two 120v supplies?

typically residential power drops in the US are a center tapped transformer winding, from step down transformer mounted on the power pole.

Indeed the center tap is bonded to neutral and earth ground, at the service panel. The two opposite polarity (same phase) ends of the centre tapped transformer winding feed banks of 120V branches. If these loads are not well balanced for current draw, significant current can flow in the neutral/center tap. If a wiring fault opens that neutral/center tap bond, the voltage will sag on the heavily loaded side, and voltage will rise on the lightly loaded side still adding up to the 240V total across the winding.   
Quote

In the UK, the 230v supply is one of three phases in a star formation with a central neutral which is bonded to ground.

in the US the high voltage distribution uses three phases, while residential power drops generally pull from only a single phase of those three. Heavy commercial users draw power from all three phases.
Quote
Domestic properties get one of the three phases, industrial properties get all three.




Steve.
Yup same here...  Just to be pedantic the two polarities of residential 120V power are the same one phase....

JR

PS: Balanced power +/- 60V AC is sometimes used in studios to reduce electrostatic fields. The worker safety issue, should help, but I'll take RCD/GFCI any day.
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Jeff Bankston

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Re: IEC C14 Madness
« Reply #15 on: December 16, 2020, 03:56:43 PM »

Live and neutral are the same size for IEC.







Steve.
Yes I know but the end that plugs into the wall will only go one way with the ground pin in place. You can continuity the ends and find which blade is the one that goes into the small slot and that will be the hot on the other end providing that the wall outlet is wired correctly. Some outlest are installed with the ground pin down and some with the ground pin up and some sideways. It probably doesnt matter on the equipment end unless someone wanted the equipment wired a certain way. It will not matter if its a 220V piece of equipment.
« Last Edit: December 16, 2020, 03:59:23 PM by Jeff Bankston »
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Jonathan Johnson

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Re: IEC C14 Madness
« Reply #16 on: December 17, 2020, 12:36:30 PM »

The larger blade/slot is always suppose to be the ground. The next larger blade/slot is always suppose to be the neutral. The smallest blade(s)/slots(s) are suppose to be the hot. This is so its foolproof or suppose to be and the ground connection has the largest connection followed by the neutral. The hot is never suppose to be on the largest connection. On all the connectors I had ever wired the ground blade/slot screw is always green color. The neutral silver. The hot gold. Always check how a device is wired if in doubt. I am a retired commercial journey/foreman electrician.

Jeff, I know that (in the US at least) the screws are supposed to denote the wire function. But, ever since I found a brand new receptacle with the silver screw on the narrow slot and the brass screw on the wide slot (someone at the factory screwed up), I've never trusted the screw colors. I always look at the face of the receptacle (or the prongs of the plug) and wire according to position.
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Steve M Smith

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Re: IEC C14 Madness
« Reply #17 on: December 18, 2020, 03:12:04 AM »

I always look at the face of the receptacle (or the prongs of the plug) and wire according to position.
It's just something else to learn, like which is pin one when soldering an XLR.




Steve.
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Brian Jojade

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Re: IEC C14 Madness
« Reply #18 on: December 23, 2020, 12:37:13 PM »

On Edison plugs, it's easier to determine hot neutral and ground because the pins are different sizes or shapes.  The round plug is ground, the bigger pin is neutral and the smallest is hot.

The C14 uses 3 pins the same size, so now you have to go on memory.

But, handily, the pins are in the exact same position as they would be on an Edison plug. So grab the Edison plug for reference and you can figure it out from there.
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Brian Jojade

ProSoundWeb Community

Re: IEC C14 Madness
« Reply #18 on: December 23, 2020, 12:37:13 PM »


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