Why won't anybody's current transformers fit through anybody's line splitters?

Jay Ashworth

Well-Known Member
I'm trying to build a pluggable power monitor to go in front of the power strips for what our British TV cousins call "derig" theatre setups -- folding tables and surface cabling in a theatre not set up for current-day equipment.

Alas, while it's easy to get this, with a 100A split-core CT:


and it's relatively easy to get this:


with only one hole in it for shortness, that's *still* a 10X current multiplying splitter, and the necessary 10 wraps of 14AWG make the posts so think the CT won't go around them... and larger CTs, 200 and 300A are too thick to fit the other way.

WHEREFORE:

Why the *hell* doesn't anyone manufacture a 1X CT sensor unit with a 5-15 plug on one side, and a 5-15 receptacle on the other, and some connector for the CT attachment, that's all a single damn unit, so I don't have to fight this battle?

The popularity of the P3 Kill-A-Watt tells me there's a market here, but if anyone's filling it, I can't find them...
 

Jay Ashworth

Well-Known Member
Alternatively, a splitter that was *only* 1X could have sufficiently thinner posts to accept the CT I can *get*...
 

jayvee

Well-Known Member
I'm trying to build a pluggable power monitor to go in front of the power strips for what our British TV cousins call "derig" theatre setups -- folding tables and surface cabling in a theatre not set up for current-day equipment.

Alas, while it's easy to get this, with a 100A split-core CT:


and it's relatively easy to get this:


with only one hole in it for shortness, that's *still* a 10X current multiplying splitter, and the necessary 10 wraps of 14AWG make the posts so think the CT won't go around them... and larger CTs, 200 and 300A are too thick to fit the other way.

WHEREFORE:

Why the *hell* doesn't anyone manufacture a 1X CT sensor unit with a 5-15 plug on one side, and a 5-15 receptacle on the other, and some connector for the CT attachment, that's all a single damn unit, so I don't have to fight this battle?

The popularity of the P3 Kill-A-Watt tells me there's a market here, but if anyone's filling it, I can't find them...
Sounds like it's time for you to get rich and patented!
 

MRW Lights

Well-Known Member
I'm not entirely sure of your application, but does a ups with active monitoring not work? I might tend to overuse them personally, but I get conditioned power with a backup...

... you're not wanting individual load monitoring of each receptacle right, only overall load?
 

Jay Ashworth

Well-Known Member
I'm not entirely sure of your application, but does a ups with active monitoring not work? I might tend to overuse them personally, but I get conditioned power with a backup...

... you're not wanting individual load monitoring of each receptacle right, only overall load?
Correct. But I'm not aware of a UPS that I can afford that will carry 15A, and give me Volts, Amps, Watts, PF, HZ, and probably VAR (I don't remember the 6th parameter) -- at least not without requiring the UPS to be up on the desk taking up space.

Plus which, this is a $30 solution, and that's a $400 solution.

Yes, I should have a UPS in that position, but...
 

MRW Lights

Well-Known Member
Correct. But I'm not aware of a UPS that I can afford that will carry 15A, and give me Volts, Amps, Watts, PF, HZ, and probably VAR (I don't remember the 6th parameter) -- at least not without requiring the UPS to be up on the desk taking up space.

Plus which, this is a $30 solution, and that's a $400 solution.

Yes, I should have a UPS in that position, but...

.... I mean as long as we assume a +/- amperage overage and assuming you wouldn't be sustaining 15A..... how about this?

 

Jay Ashworth

Well-Known Member
Yup, I'm familiar with the Kill-a-Watt products. Still trying not to put the power up on the desk, though... :)
Whether I'll be sustaining 15A I don't know; that's sort of why I want to measure.

Also, that requires me to pick a parameter.
 

MRW Lights

Well-Known Member
Yup, I'm familiar with the Kill-a-Watt products. Still trying not to put the power up on the desk, though... :)
Whether I'll be sustaining 15A I don't know; that's sort of why I want to measure.

Also, that requires me to pick a parameter.

I need more room in my brain for not these things.... How does this fit your form factor? Don't look at the price tag, see if it works then figure out how to buy it and where to put it ;)

 

Jay Ashworth

Well-Known Member
I need more room in my brain for not these things.... How does this fit your form factor? Don't look at the price tag, see if it works then figure out how to buy it and where to put it ;)

Surplus smart PDUs are not hard to find on eBay either, and I hadn't thought about this -- though these tend to be geared towards putting a rackfull of C13 servers on a 20A or 30A pigtail. But yeah, this isn't a bad approach; I'll go check out the state of the market. Nice get; thanks.
 

FMEng

Well-Known Member
Fight Leukemia
Unless this has to be factory made, UL approved, etc: Wire a 5-15P to a 5-15R with three, single conductor wires of appropriate ampacity (black, white, green), a few inches long. Put the clamp around the black wire.
 

Jay Ashworth

Well-Known Member
Unless this has to be factory made, UL approved, etc: Wire a 5-15P to a 5-15R with three, single conductor wires of appropriate ampacity (black, white, green), a few inches long. Put the clamp around the black wire.
Well, sure. I took electricity at votech, I know how to make a splitter. And no it doesn't have to be UL listed, but on the other side of the coin I didn't want to burn anybody's theater down either. :)
 

Jay Ashworth

Well-Known Member
SIDEBAR: This thread is an *excellent* example of a thing we call the A-B problem in Tech Support; AKA "you're fixing the wrong problem". It's always a good idea to evaluate for A-B when you get stuck on something; maybe *you're* trying to solve the wrong problem too...
 

MRW Lights

Well-Known Member
SIDEBAR: This thread is an *excellent* example of a thing we call the A-B problem in Tech Support; AKA "you're fixing the wrong problem". It's always a good idea to evaluate for A-B when you get stuck on something; maybe *you're* trying to solve the wrong problem too...
I would actually give you credit for starting great brainstorming conversations about unique "we've always done it this way" sort of problems...

might not be the wrong problem we're solving, but maybe we're not asking the right questions....
 

Jay Ashworth

Well-Known Member
I would actually give you credit for starting great brainstorming conversations about unique "we've always done it this way" sort of problems...

might not be the wrong problem we're solving, but maybe we're not asking the right questions....
It's really what I've done for a living for mumble years. :)
 

STEVETERRY

Well-Known Member
SIDEBAR: This thread is an *excellent* example of a thing we call the A-B problem in Tech Support; AKA "you're fixing the wrong problem". It's always a good idea to evaluate for A-B when you get stuck on something; maybe *you're* trying to solve the wrong problem too...
"When you hear hoof beats, don't suspect Zebras"
 

Jay Ashworth

Well-Known Member
A common rendering of the quote, Steve, but I've been told -- and the only complete citation I can('t) find is the one I posted in my long dead blog -- that the medical professor who originated that quote actually said:

"When you hear hoofbeats behind you on Greene St, you expect to see a horse, not a zebra, but a zebra it may well be."

I myself was quoting someone who was one of his med students in that time period, so I assumed she had it right... but you can see that the underlying sense of the quote is exactly the opposite of what most people use it to mean.
 

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