Why two neutral camlok inputs?

It will be a while before I can set up this experiment. My hypothesis is that the most neutral current will be seen when one phase's sub is at Full, another at 50%, and the third at zero. I'll let you know.

Here is some real Neutral History in the attached file. I did this around 1981. We were having weekly Code revision meetings at See Factor (boy, were we young and full of piss-and-vinegar!). Mitch Hefter said to me: "SCR dimmers can generate neutral currents in excess of the maximum phase current." "Impossible!" said I, and then went back to my shop to prove it. Oops! I proved Mitch's statement, and the gory details are attached.

This was the start of the work we did in the 1987 Code to require upsized neutrals on phase-control dimmers. I don't think many people in the electrical community were even aware of "harmonics" or "non-linear loads" at that point.

Note the Courier typeface generated by my Diablo 630 printer driven by an Altair 8800 computer running Wordstar!

Enjoy!

ST
 

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Need to make a CamLoc to 24way Edison AC distro for a show leaving in about two or three weeks. Either going to build it myself or if the only supplier that has not walked out of the bid given short notice can get my specifications for it according to what I specified actually on the drawing and quote instead of what artistic licence they feel like it in quoting it out, either I'll build it if cost effective or they will. Should know in the morning, in the mean time suppliers for the components I would put in it are also taking their own sweat time in me asking to know all info by the end of today about pricing etc.

In my case the four phase breaker with 60% neutral sensing with GFCI, adjustable loading amperage trip ratios and in-breaker amperage sensor as with trouble shooting diagnostics is in my concepept for main breaker as compliant with a sort of feeling for how things are going these days. Ok, such a thing would cost at least $5K and not in price but in lead time I scaled down from that a bit but not by much in still pressing for what neutral sensing and GFCI is a good idea for something I'm building. The other place that can get it done in time... they are UL listed but won't supply a fan for the rack in if I do so they say it than voids warranty. This much less only supplying normal three phase breakers and its' a fight to supply on the drawing a six wire system for feeding it amongst other design changes that one just has to ask where did these changes come from in me specifying part numbers and only wanted a quote on what I specified not something totally different. Days wasted... almost two weeks now in me just finding a supplier, getting a quote and getting it defined how I asked for it and still not done yet. The guys making it will no doubt be cursing me for requesting such a thing on such short notice yet it their own sales people that took their own sweet time before either deciding after waiting a while they couldn't supply or still refining their design to my specifications that down to the part number were correct they just took artistic licence with them. Stuff like five wire instead of six wire supplies.... If I specified a six wire supply with specific part number, why on the quote would a five wire suddenly become what's quoted? That lost at least a day in changing that and other artistic licence stuff - at least.

Not a discussion on "you should contact these guys" they have always done well by me, more a concept of current UL listings of gear and or easy plug in type done before thus is former or current code compliant plus easy to do and it's going to be a while until things change makes gear hard to make proper according to the latest concepts in what should be done code or not. If I'm offering to pay an extera $K in money for a new fangled proper breaker be it GFCI, neutral sensing four wire or both... only been told so far... nope, can't do that even if better or safer. This at best above pre-made component based power supplies that can't be done on a two week notice... Suppliers and experts heck... they respond back normally this is what we are listed for and what has always worked in the past. Breaker manufacturers are more concerned about legal stances about... if they specify a proper breaker for say the Hunguro Flash strobe light, they might be liable for it than... than in wasting a week doing anything to help. Industry just wasting my time with compliance of the past set ways and legal problems in helping me get my job done. Stand in my way you get stepped on and I don't normally travel back down those stairs.



Certain other panels I need and bidded out I sent photos of. Similar questions on how to, it's not how we do it, this is how we do it for about double as much as it costs you to do it. Yet nobody was able to make a panel from scratch given a limited lead time cost effective to my specifications and that's all falling back to me. A lot of electrical panels to wire up in the coming weeks including possibly the above.


Big challenges for me: given the options in commercial grade breakers - well beyond QO or QOU types we get into trip ratios for voltages the breaker won't see etc. in headackes of not so well defined tables. Choosing the main breaker - big problems in getting leading edge in technology simply from the education standpoint.

Second, getting a quote for what you want even if you specify the part numbers for the components in the rack you want - still often takes at least a day or more for a price quote. This much less even if specifying part numbers, getting the quote for what you asked for can be challenging in wasting days that could have been spent building the thing in either in the end it can or most often is not enough time left to build it.

Next and while I have a GreenLee punch that will punch say an Edison outlet, and even have a jig for that punch made up, my time is valuable and it's a pain in the rear to punch Edison outlets. Such panels pre-made need to be more available and no doubt are. Takes time to even quote out such things.

Pain in the rear to make a AC distro rack, this much less one that can travel the world. Not sufficiently trained for circuit breaker technology and the suppliers of such gear need longer lead times than is often available or reasonable no matter the cost, pre-punched gear even if listed in catalogs is not persay available on short notice, sales people take their own sweat time in quoting prices no matter if breaker or panel, breakers especially if high tech take weeks to construct and cost thousands of dollars each etc.

Welcome to my world, but my current goals are first to supply feed thru CamLocs, next to supply six wire for anything 120v, next to get into the GFCI and neutral sensing breaker world. Next to asside from Middle Atlantic's component base rack system, get pre-punched panel suppliers that can just ship them on limited notice because if in the catalog, that means it's something pre-designed and easy to supply. After that, it's a few $K in rack, if I want something special which makes sense to have you don't say you cannot do that.

Yep, the last week or so I have been working with the issues of this discussion in rack panels, six wire and breaker types a lot. Spent the entire morning reading various Cutler Hammer catalogs on their breakers to say the least. Wound up with a headache instead of answers as to which specific circuit breaker was the one I wanted by part number. Neither did my sales rep. for them end up with any different. Still waiting on her tech support to reply a day or two later.

Welcome to my world. While for sure harder to do what's proper and the way the trends are going it's still my intent for very valid reasons. Little steps perhaps in the end.
 
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Need to make a CamLoc to 24way Edison AC distro for a show leaving in about two or three weeks. Either going to build it myself or if the only supplier that has not walked out of the bid given short notice can get my specifications for it according to what I specified actually on the drawing and quote instead of what artistic licence they feel like it in quoting it out, either I'll build it if cost effective or they will. Should know in the morning, in the mean time suppliers for the components I would put in it are also taking their own sweat time in me asking to know all info by the end of today about pricing etc.

In my case the four phase breaker with 60% neutral sensing with GFCI, adjustable loading amperage trip ratios and in-breaker amperage sensor as with trouble shooting diagnostics is in my concepept for main breaker as compliant with a sort of feeling for how things are going these days. Ok, such a thing would cost at least $5K and not in price but in lead time I scaled down from that a bit but not by much in still pressing for what neutral sensing and GFCI is a good idea for something I'm building. The other place that can get it done in time... they are UL listed but won't supply a fan for the rack in if I do so they say it than voids warranty. This much less only supplying normal three phase breakers and its' a fight to supply on the drawing a six wire system for feeding it amongst other design changes that one just has to ask where did these changes come from in me specifying part numbers and only wanted a quote on what I specified not something totally different. Days wasted... almost two weeks now in me just finding a supplier, getting a quote and getting it defined how I asked for it and still not done yet. The guys making it will no doubt be cursing me for requesting such a thing on such short notice yet it their own sales people that took their own sweet time before either deciding after waiting a while they couldn't supply or still refining their design to my specifications that down to the part number were correct they just took artistic licence with them. Stuff like five wire instead of six wire supplies.... If I specified a six wire supply with specific part number, why on the quote would a five wire suddenly become what's quoted? That lost at least a day in changing that and other artistic licence stuff - at least.

Not a discussion on "you should contact these guys" they have always done well by me, more a concept of current UL listings of gear and or easy plug in type done before thus is former or current code compliant plus easy to do and it's going to be a while until things change makes gear hard to make proper according to the latest concepts in what should be done code or not. If I'm offering to pay an extera $K in money for a new fangled proper breaker be it GFCI, neutral sensing four wire or both... only been told so far... nope, can't do that even if better or safer. This at best above pre-made component based power supplies that can't be done on a two week notice... Suppliers and experts heck... they respond back normally this is what we are listed for and what has always worked in the past. Breaker manufacturers are more concerned about legal stances about... if they specify a proper breaker for say the Hunguro Flash strobe light, they might be liable for it than... than in wasting a week doing anything to help. Industry just wasting my time with compliance of the past set ways and legal problems in helping me get my job done. Stand in my way you get stepped on and I don't normally travel back down those stairs.



Certain other panels I need and bidded out I sent photos of. Similar questions on how to, it's not how we do it, this is how we do it for about double as much as it costs you to do it. Yet nobody was able to make a panel from scratch given a limited lead time cost effective to my specifications and that's all falling back to me. A lot of electrical panels to wire up in the coming weeks including possibly the above.


Big challenges for me: given the options in commercial grade breakers - well beyond QO or QOU types we get into trip ratios for voltages the breaker won't see etc. in headackes of not so well defined tables. Choosing the main breaker - big problems in getting leading edge in technology simply from the education standpoint.

Second, getting a quote for what you want even if you specify the part numbers for the components in the rack you want - still often takes at least a day or more for a price quote. This much less even if specifying part numbers, getting the quote for what you asked for can be challenging in wasting days that could have been spent building the thing in either in the end it can or most often is not enough time left to build it.

Next and while I have a GreenLee punch that will punch say an Edison outlet, and even have a jig for that punch made up, my time is valuable and it's a pain in the rear to punch Edison outlets. Such panels pre-made need to be more available and no doubt are. Takes time to even quote out such things.

Pain in the rear to make a AC distro rack, this much less one that can travel the world. Not sufficiently trained for circuit breaker technology and the suppliers of such gear need longer lead times than is often available or reasonable no matter the cost, pre-punched gear even if listed in catalogs is not persay available on short notice, sales people take their own sweat time in quoting prices no matter if breaker or panel, breakers especially if high tech take weeks to construct and cost thousands of dollars each etc.

Welcome to my world, but my current goals are first to supply feed thru CamLocs, next to supply six wire for anything 120v, next to get into the GFCI and neutral sensing breaker world. Next to asside from Middle Atlantic's component base rack system, get pre-punched panel suppliers that can just ship them on limited notice because if in the catalog, that means it's something pre-designed and easy to supply. After that, it's a few $K in rack, if I want something special which makes sense to have you don't say you cannot do that.

Yep, the last week or so I have been working with the issues of this discussion in rack panels, six wire and breaker types a lot. Spent the entire morning reading various Cutler Hammer catalogs on their breakers to say the least. Wound up with a headache instead of answers as to which specific circuit breaker was the one I wanted by part number. Neither did my sales rep. for them end up with any different. Still waiting on her tech support to reply a day or two later.

Welcome to my world. While for sure harder to do what's proper and the way the trends are going it's still my intent for very valid reasons. Little steps perhaps in the end.

A few thoughts:

1.For the kind of money you will spend, I would want a UL1640-listed distro. That leaves out making it yourself, unless your shop is a Listed Assembler.

2. Why do you want neutral overcurrent sensing on the main breaker? If the distro is designed for any overcurrent, it should not be needed. The feeder to the company switch certainly will not have it.

3. I am not clear if you are thinking about GFCI protection on the main breaker, but if so, I would be cautious. Not all GFCI mains work with non-linear loads (talk to Bender or K-Tec about ones that will), and adjustable GFP (ground fault protection for equipment only) main breakers (30ma to 300ma or so) do not provide personnel protection.

4. If you need high-inrush breakers to deal with the strobes, I suggest a fully magnetic type from Airpax or Carling that has a specific high inrush curve.

ST
 
Still have a lot to learn on distros and modern technologies available these days. For the money to spend I invested it in the end in a supplier that could get it done on short notice, within less budget and with UL listing for what gear I specified. Gonna spend more time on doing that specifying while I learn more into breaker types to match my wishes and or what I think most appropriate especially in this case for a at random load under uncertain show conditions in use. I was covering the basics in what I was wanting but in the end went for experience more than I have. Still the initial merits I'll study into.

The strobes were a different AC distro I also in the end farmed out in not being ready to do the work on. Getting closer.




A few thoughts:

1.For the kind of money you will spend, I would want a UL1640-listed distro. That leaves out making it yourself, unless your shop is a Listed Assembler.

2. Why do you want neutral overcurrent sensing on the main breaker? If the distro is designed for any overcurrent, it should not be needed. The feeder to the company switch certainly will not have it.

3. I am not clear if you are thinking about GFCI protection on the main breaker, but if so, I would be cautious. Not all GFCI mains work with non-linear loads (talk to Bender or K-Tec about ones that will), and adjustable GFP (ground fault protection for equipment only) main breakers (30ma to 300ma or so) do not provide personnel protection.

4. If you need high-inrush breakers to deal with the strobes, I suggest a fully magnetic type from Airpax or Carling that has a specific high inrush curve.

ST
 
My understanding from the brief coverage I got about this subject was in the Theater industry or touring where you're using dimming systems.

So the issue with these types of systems and being 3 Phase is they all need to be in balance within 30 AMPs. Now when you're working on a Film set for example (which is what I'm going to be doing). Everything is balanced out within that 30 AMP margin and for the most part it doesn't change and there's no excessive difference. If there was you'd blow the genny or transformer not only that but you could also fry the cabling on the neutral as it's only rated for 200 AMPs. Phase 1 - 200 AMP Phase 2 - 200 Amp Phase 3 - 200 AMP (600 AMP). Neutral as close to balance but if all of the sudden it goes out of balance and you're sending 250 AMPs down that neutral you'll fry it.

So in the case of going back to theater where at one moment you might have a few lights on then the very next moment you'll have the whole stage lit. You're constantly going in and out of balance. Thus you need two neutrals to cover the unbalanced amount.
 
remember that this only applies IF you are running at the full capacity of the cable system ie a full 200 amps say. Usually this is not the case. same as the Generator or transformer most of the genorators are rated way beyond the full capacity demand.
Sharyn
 
Please try to grasp this concept, I apologize for the capitals it is important
BALANCING YOUR LOAD WILL NOT SOLVE YOUR NEUTRAL PROBLEMS, WITH DIMMERS, WITH A TOTALLY BALANCED LOAD, YOUR NEUTRAL CURRENT WILL GO WELL OVER 120% OF PHASE CURRENT AT 50% DIMMER LEVELS.
An imbalance will raise the neutral up to 130% or so but you cannot, it is impossible to avoid these high neutral currents.Steve has mentioned this often but the point has been missed.
 

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