Comments on: Split The Conductors For Easy Current Measurement http://toolmonger.com/2008/12/03/split-the-conductors-for-measuring-load/ All tools. All the time. Your source for news, information, and reviews of hand tools, power tools, and tools of all kinds. Sun, 22 Nov 2009 20:55:45 +0000 http://wordpress.org/?v=2.6.1 By: David Bryan http://toolmonger.com/2008/12/03/split-the-conductors-for-measuring-load/#comment-694530 David Bryan Sun, 07 Dec 2008 09:13:12 +0000 http://toolmonger.com/?p=16402#comment-694530 I've read up on that Navy story quite a bit and I just can't bring myself to buy it. There's just something fishy about it, nautically speaking. The other one is just not how things work. I used to hear all kinds of whoppers at safety meetings. I've told a bunch of 'em myself, usually involving death, evisceration, mutilation, etc. And I know some really ugly, sometimes improbable true ones. But if these stories help somebody be safer there's something to be said for them. You'll shoot your eye out, you'll break your neck, you'll atrially fibrillate yourself, if you don't watch out. I’ve read up on that Navy story quite a bit and I just can’t bring myself to buy it. There’s just something fishy about it, nautically speaking. The other one is just not how things work. I used to hear all kinds of whoppers at safety meetings. I’ve told a bunch of ‘em myself, usually involving death, evisceration, mutilation, etc. And I know some really ugly, sometimes improbable true ones. But if these stories help somebody be safer there’s something to be said for them. You’ll shoot your eye out, you’ll break your neck, you’ll atrially fibrillate yourself, if you don’t watch out.

]]> By: Pierson http://toolmonger.com/2008/12/03/split-the-conductors-for-measuring-load/#comment-692877 Pierson Fri, 05 Dec 2008 18:07:47 +0000 http://toolmonger.com/?p=16402#comment-692877 Zathrus, The killer 9 volt lithium battery sounds like a classic "friend of a friend story." You know, the kind that starts, "A firend of mine told me about this guy he knew who..." The only nine volt batteries that people test with their tongues are the little ones you put (are used to put) in radios. There is not enough current in them to melt anything, no matter what you do. a 9 volt battery is actually a package of 6 tiny 1.5 volt batteries. Thus, each battery has a very low current output, no matter what chemistry is used. Further, lithium batteries do not have current limiters in them. No batteries do. Zathrus,

The killer 9 volt lithium battery sounds like a classic “friend of a friend story.” You know, the kind that starts, “A firend of mine told me about this guy he knew who…”

The only nine volt batteries that people test with their tongues are the little ones you put (are used to put) in radios. There is not enough current in them to melt anything, no matter what you do. a 9 volt battery is actually a package of 6 tiny 1.5 volt batteries. Thus, each battery has a very low current output, no matter what chemistry is used.

Further, lithium batteries do not have current limiters in them. No batteries do.

]]> By: Toolmonger » Blog Archive » The Week in Tools: Toolmonger Top 5 http://toolmonger.com/2008/12/03/split-the-conductors-for-measuring-load/#comment-692860 Toolmonger » Blog Archive » The Week in Tools: Toolmonger Top 5 Fri, 05 Dec 2008 17:30:43 +0000 http://toolmonger.com/?p=16402#comment-692860 [...] Split The Conductors For Easy Current Measurement If you want to monitor the power consumption of a single appliance the old-school way — with a clamp-on ammeter — try an AC line splitter like this one from Elenco. The problem is, you can’t just clamp an ammeter over a power cord and measure how much juice the appliance is taking;  you need access to a single conductor to measure the current.  That’s where this tool comes in handy — rather than ruin a power cord you can just plug in the line splitter. [...] [...] Split The Conductors For Easy Current Measurement If you want to monitor the power consumption of a single appliance the old-school way — with a clamp-on ammeter — try an AC line splitter like this one from Elenco. The problem is, you can’t just clamp an ammeter over a power cord and measure how much juice the appliance is taking;  you need access to a single conductor to measure the current.  That’s where this tool comes in handy — rather than ruin a power cord you can just plug in the line splitter. [...]

]]> By: Zathrus http://toolmonger.com/2008/12/03/split-the-conductors-for-measuring-load/#comment-692260 Zathrus Thu, 04 Dec 2008 19:41:42 +0000 http://toolmonger.com/?p=16402#comment-692260 @PutnamEco: That always reminds me of a story I heard about the early Li batteries. Executives were going through the labs, engineers were showing this new 9V lithium battery that would last years. An executive picked it up, stuck out his tongue, and before he could "test" it, the engineer grabbed it from his hand. The engineer then took a small copper rod and shorted the battery terminals. The copper rod evaporated. Since it was an engineering sample, it didn't have a current limiter in it in case of short circuit... And, of course, there's also the (true story of a Navy seaman managing to kill himself with a multimeter powered by a 9V battery (hint: your external electrical resistance is in the thousands of Ohms. Your internal electrical resistance is rather considerably less and tends to go through your heart). @PutnamEco:

That always reminds me of a story I heard about the early Li batteries. Executives were going through the labs, engineers were showing this new 9V lithium battery that would last years. An executive picked it up, stuck out his tongue, and before he could “test” it, the engineer grabbed it from his hand.

The engineer then took a small copper rod and shorted the battery terminals.

The copper rod evaporated.

Since it was an engineering sample, it didn’t have a current limiter in it in case of short circuit…

And, of course, there’s also the (true story of a Navy seaman managing to kill himself with a multimeter powered by a 9V battery (hint: your external electrical resistance is in the thousands of Ohms. Your internal electrical resistance is rather considerably less and tends to go through your heart).

]]> By: PutnamEco http://toolmonger.com/2008/12/03/split-the-conductors-for-measuring-load/#comment-691750 PutnamEco Thu, 04 Dec 2008 12:58:43 +0000 http://toolmonger.com/?p=16402#comment-691750 Re: #91 Who hasn't "licked" a nine volt battery to see if it was good or not? Re: #91

Who hasn’t “licked” a nine volt battery to see if it was good or not?

]]> By: Chris http://toolmonger.com/2008/12/03/split-the-conductors-for-measuring-load/#comment-691100 Chris Thu, 04 Dec 2008 04:05:10 +0000 http://toolmonger.com/?p=16402#comment-691100 To be fair, #91 did say "low" :-p cl To be fair, #91 did say “low” :-p

cl

]]> By: Benjamen Johnson http://toolmonger.com/2008/12/03/split-the-conductors-for-measuring-load/#comment-690751 Benjamen Johnson Wed, 03 Dec 2008 23:44:40 +0000 http://toolmonger.com/?p=16402#comment-690751 Wow, I have to eat crow twice for one post. David Bryan, You are absolutely right, the Megger does measure current in multiple conductors, but you have to know the distance between the conductors. It uses the fact the fields don't overlap completely to figure out the current. I'm surprised they can sell a consumer products that can measure the fields precisely enough to do this, let alone for $300. Thanks, David. This is good. I'll have to post about it in a while. Wow, I have to eat crow twice for one post.

David Bryan, You are absolutely right, the Megger does measure current in multiple conductors, but you have to know the distance between the conductors. It uses the fact the fields don’t overlap completely to figure out the current. I’m surprised they can sell a consumer products that can measure the fields precisely enough to do this, let alone for $300.

Thanks, David. This is good. I’ll have to post about it in a while.

]]> By: Old Coot http://toolmonger.com/2008/12/03/split-the-conductors-for-measuring-load/#comment-690737 Old Coot Wed, 03 Dec 2008 23:33:59 +0000 http://toolmonger.com/?p=16402#comment-690737 David Bryan: My rule only applies to electrical and mechanical things. David Bryan: My rule only applies to electrical and mechanical things.

]]> By: David Bryan http://toolmonger.com/2008/12/03/split-the-conductors-for-measuring-load/#comment-690689 David Bryan Wed, 03 Dec 2008 23:04:12 +0000 http://toolmonger.com/?p=16402#comment-690689 I'm not touching that one. I’m not touching that one.

]]> By: Old Coot http://toolmonger.com/2008/12/03/split-the-conductors-for-measuring-load/#comment-690684 Old Coot Wed, 03 Dec 2008 22:59:20 +0000 http://toolmonger.com/?p=16402#comment-690684 David Bryant: I'm almost afraid to ask about #91 as it likely violates my rule which states: Fingers, sometimes; tongue, no way/no how. David Bryant: I’m almost afraid to ask about #91 as it likely violates my rule which states: Fingers, sometimes; tongue, no way/no how.

]]> By: David Bryan http://toolmonger.com/2008/12/03/split-the-conductors-for-measuring-load/#comment-690678 David Bryan Wed, 03 Dec 2008 22:56:59 +0000 http://toolmonger.com/?p=16402#comment-690678 Benjamin-- I don't know how they do it. These days I am but a lowly recreational romex jerker, at best, for the most part. But the Megger model MMC850 is supposed to do it, and I think I've seen another one that will too. They say it'll work for one, two, or three conductors. What a smart little machine it must be. Benjamin– I don’t know how they do it. These days I am but a lowly recreational romex jerker, at best, for the most part. But the Megger model MMC850 is supposed to do it, and I think I’ve seen another one that will too. They say it’ll work for one, two, or three conductors. What a smart little machine it must be.

]]> By: David Bryan http://toolmonger.com/2008/12/03/split-the-conductors-for-measuring-load/#comment-690637 David Bryan Wed, 03 Dec 2008 22:29:16 +0000 http://toolmonger.com/?p=16402#comment-690637 Well, I'll run through some of the topic headings: 90. Electricians often test circuits for the presence of voltage by touching the conductors with the fingers. 91. The presence of low voltages can be determined by "tasting." 93. A telephone receiver in combination with one or two dry cells constitutes an excellent equipment for certain tests. 95. A telegraph sounder is sometimes used for testing. 96. An electric bell outfit for testing. 113. How to Make a Slide-Wire Bridge 119. Testing Cables For Insulation with a Telephone Receiver and Battery That scratches the surface. There's a bunch of tricks for determining DC polarity too. I just found my "Modern Electrical Construction" from 1904, now I'll have to look through that one. Well, I’ll run through some of the topic headings:
90. Electricians often test circuits for the presence of voltage by touching the conductors with the fingers.
91. The presence of low voltages can be determined by “tasting.”
93. A telephone receiver in combination with one or two dry cells constitutes an excellent equipment for certain tests.
95. A telegraph sounder is sometimes used for testing.
96. An electric bell outfit for testing.
113. How to Make a Slide-Wire Bridge
119. Testing Cables For Insulation with a Telephone Receiver and Battery
That scratches the surface. There’s a bunch of tricks for determining DC polarity too.
I just found my “Modern Electrical Construction” from 1904, now I’ll have to look through that one.

]]> By: Benjamen Johnson http://toolmonger.com/2008/12/03/split-the-conductors-for-measuring-load/#comment-690620 Benjamen Johnson Wed, 03 Dec 2008 22:17:42 +0000 http://toolmonger.com/?p=16402#comment-690620 David Bryan: You are correct, it's not really very straight forward monitoring power with a clamp-on ammeter. Unless you have a logging ammeter and make a few assumptions you've better off doing it another way. I was more concerned with the comments in the Black & Decker Power Monitor post and wasn't really thinking when I wrote the line about monitoring power. I would like you to explain how you can get a clamp on ammeter to work over "multiple conductor cords" though. I'm assuming you mean a cord with current flowing in one direction on one conductor and the other on the second. If the two fields don't cancel each other out you're leaking current to ground somewhere and if you were using a GFI it would trip. David Bryan:

You are correct, it’s not really very straight forward monitoring power with a clamp-on ammeter. Unless you have a logging ammeter and make a few assumptions you’ve better off doing it another way.

I was more concerned with the comments in the Black & Decker Power Monitor post and wasn’t really thinking when I wrote the line about monitoring power.

I would like you to explain how you can get a clamp on ammeter to work over “multiple conductor cords” though. I’m assuming you mean a cord with current flowing in one direction on one conductor and the other on the second. If the two fields don’t cancel each other out you’re leaking current to ground somewhere and if you were using a GFI it would trip.

]]> By: Old Coot http://toolmonger.com/2008/12/03/split-the-conductors-for-measuring-load/#comment-690608 Old Coot Wed, 03 Dec 2008 22:09:04 +0000 http://toolmonger.com/?p=16402#comment-690608 David Bryant: Good information, thanks. It would be fascinating to see some of those 1913 testing ideas; would it be possible to post some of them? David Bryant: Good information, thanks. It would be fascinating to see some of those 1913 testing ideas; would it be possible to post some of them?

]]> By: David Bryan http://toolmonger.com/2008/12/03/split-the-conductors-for-measuring-load/#comment-690584 David Bryan Wed, 03 Dec 2008 21:47:53 +0000 http://toolmonger.com/?p=16402#comment-690584 This ain't how you monitor AC power usage. It's not even how you determine instantaneous AC power. When you measure instantaneous current, you find out what the instantaneous current is, and that's about all. That can be real handy, and sometimes it's exactly what you need to know, but it's not monitoring power usage. It's not even "monitoring" current, and knowing current and voltage alone will not give you power in an AC circuit. If you also know that it is a purely resistive circuit, it can. This technique can give you useful information, but it shouldn't be confused with monitoring power. For that you need information over a period of time. You don't pay for kilowatts-- you pay for kilowatt-hours. This gives you neither kilowatts nor hours. There are clamp-on meters that work for multiple-conductor cords. And a good line splitter, as the article says, does a number of things for you besides split the line. Toolhearty does have the best quick way of making a usable, field expedient line splitter in his flat-cord method. And I've got a first-edition American Electrician's Handbook from 1913 with all kinds of stuff about testing with your fingers. This ain’t how you monitor AC power usage. It’s not even how you determine instantaneous AC power. When you measure instantaneous current, you find out what the instantaneous current is, and that’s about all. That can be real handy, and sometimes it’s exactly what you need to know, but it’s not monitoring power usage. It’s not even “monitoring” current, and knowing current and voltage alone will not give you power in an AC circuit. If you also know that it is a purely resistive circuit, it can. This technique can give you useful information, but it shouldn’t be confused with monitoring power. For that you need information over a period of time. You don’t pay for kilowatts– you pay for kilowatt-hours. This gives you neither kilowatts nor hours.
There are clamp-on meters that work for multiple-conductor cords. And a good line splitter, as the article says, does a number of things for you besides split the line. Toolhearty does have the best quick way of making a usable, field expedient line splitter in his flat-cord method.
And I’ve got a first-edition American Electrician’s Handbook from 1913 with all kinds of stuff about testing with your fingers.

]]> By: Toolaremia http://toolmonger.com/2008/12/03/split-the-conductors-for-measuring-load/#comment-690509 Toolaremia Wed, 03 Dec 2008 20:57:25 +0000 http://toolmonger.com/?p=16402#comment-690509 Ben, Ben there, done that. When I was 3 years old! Now I'm an Electrical Engineer. Go figure. Ben,

Ben there, done that. When I was 3 years old! Now I’m an Electrical Engineer. Go figure.

]]> By: Benjamen Johnson http://toolmonger.com/2008/12/03/split-the-conductors-for-measuring-load/#comment-690433 Benjamen Johnson Wed, 03 Dec 2008 20:12:06 +0000 http://toolmonger.com/?p=16402#comment-690433 I don't understand why I should by a voltage tester when I can just stick my finger in the socket and see if I get shocked... I don’t understand why I should by a voltage tester when I can just stick my finger in the socket and see if I get shocked…

]]> By: KMR http://toolmonger.com/2008/12/03/split-the-conductors-for-measuring-load/#comment-690383 KMR Wed, 03 Dec 2008 19:38:48 +0000 http://toolmonger.com/?p=16402#comment-690383 Thats what I suggested last week... I just don't get why I'm going to spend $15 on a single purpose tool when I've got extension cords lying all over. Thats what I suggested last week… I just don’t get why I’m going to spend $15 on a single purpose tool when I’ve got extension cords lying all over.

]]> By: Toolhearty http://toolmonger.com/2008/12/03/split-the-conductors-for-measuring-load/#comment-690320 Toolhearty Wed, 03 Dec 2008 18:55:28 +0000 http://toolmonger.com/?p=16402#comment-690320 ...or just use a short, flat extension cord and separate the insulated conductors. …or just use a short, flat extension cord and separate the insulated conductors.

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