Another silly power question
- Thread startermikeosoft
- Start date
Thus my not being sufficient these days to post on such matters in now educating or refreshing me. Thanks stevetery for the long form version of your reply. You are very vibrant and necessay in this post to all and thanks for doing the long form.
I have the like 1999 version of the handbook as with that version of American Electrician's Handbook which is more extensive.
At some point, you really do have to buy and read cover to cover as best you can if want to be serious about code. No internet skipping around will solve the general stuff that comes up. That if serious about your own doing wiring. Neither are cheap but I would think while really boring especially in many chapters - if you want to become an electrician.. good to buy and try as hard as you can to read the hard cover version of.
As said, once you get the concept, keeping up with code changes stems from something already known about. That's the easy part in even making your own.
I have the like 1999 version of the handbook as with that version of American Electrician's Handbook which is more extensive.
At some point, you really do have to buy and read cover to cover as best you can if want to be serious about code. No internet skipping around will solve the general stuff that comes up. That if serious about your own doing wiring. Neither are cheap but I would think while really boring especially in many chapters - if you want to become an electrician.. good to buy and try as hard as you can to read the hard cover version of.
As said, once you get the concept, keeping up with code changes stems from something already known about. That's the easy part in even making your own.
Last edited:
Let's go slightly generalised for a moment here, I don't know the specifics of the packs in question.
You can broadly break a dimmer down into 2 parts - the control side (generally running at extra low voltage) and the power side running at a somewhat higher voltage.
generally the trigger link between control and power will be an optocupler so inherently you have galvanic isolation between control and power at that point. (We'll ignore for now the sensing circuits neccessary to detect the zero crossings etc.)
Given that galvanic isolation, there is no reason why each power "block" if we can call it that, can't be fed from a different source, because the only copper connections will be mains in and mains (dimmed) out.
So say you have 6 dimmer "blocks" in a pack - then you busbar the actives and neutrals of 3 of them to one incoming supply lead and separately busbar the other 3 to a second supply lead.
Importantly you DO NOT bond the neutrals. You DO bond the Earths though...
You can broadly break a dimmer down into 2 parts - the control side (generally running at extra low voltage) and the power side running at a somewhat higher voltage.
generally the trigger link between control and power will be an optocupler so inherently you have galvanic isolation between control and power at that point. (We'll ignore for now the sensing circuits neccessary to detect the zero crossings etc.)
Given that galvanic isolation, there is no reason why each power "block" if we can call it that, can't be fed from a different source, because the only copper connections will be mains in and mains (dimmed) out.
So say you have 6 dimmer "blocks" in a pack - then you busbar the actives and neutrals of 3 of them to one incoming supply lead and separately busbar the other 3 to a second supply lead.
Importantly you DO NOT bond the neutrals. You DO bond the Earths though...
Hang on, you don't see the problem with trailer owners needing to perform an optional test?
What's more one that requires the purchase of additional equipment...
Warning bells at 200 metres
So if for a moment we neglect the option of a miswired outlet, how about the usage case where only one plug is in use but is drawing a full 30 amps.
There will be a few volts voltage drop across the neutral conductor meaning that exposed neutral pin will NOT be at 0v. Enough voltage to cause serious injury under normal circumstances - probably not, but a risk none the less. Add damp conditions around it (not unexpected in a caravan park) though and things could really get fun...
This is no different than any other shared neutral situation where linked breakers are required. The plug/s and socket/s are effectively a breaker and thus must be linked...
Just don't try and prove the connection between that and the code
STEVETERRY
Well-Known Member
Ahem....
406.7 Attachment Plugs, Cord Connectors, and Flanged Surface Devices.
(B) Connection of Attachment Plugs. Attachment plugs shall be installed so that their prongs, blades, or pins are not energized unless inserted into an energized receptacle or cord connectors. No receptacle shall be installed so as to require the insertion of an energized attachment plug as its source of supply.
The requirements in 406.7(B) were originally found in product information only. However, as an aid to the inspection community, these requirements are now clearly stated in the NEC. A live attachment plug cap can be a dangerous situation. Attachment plug caps should never be installed so as to allow the blades to be energized without being plugged into a device.
ST
STEVETERRY
Well-Known Member
JD
Well-Known Member
Well, yes and no. Each AC input must have it's own step-down transformer to the control circuit. That way, the zero-voltage cross detector for the dimmers maintains phase relationship with the incoming power for those dimmers. Otherwise, if the second AC input was plugged into a receptacle on a different phase leg, the trigger circuit would be firing at the wrong time.
Last edited:
