Just for fun:

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rattus

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Say a color-blind electrician comes across a piece of conduit with three black wires and an EGC protruding from it. How would he, with only a 2-lead neon tester, determine if this is a,

3-ph delta service?
3-ph wye service with a missing neutral?
1-ph 120/240 service?
3-wire 2-ph service?
 
The same way anyone else would!

Most colorblind people are red-green or blue-yellow color blind.
If they are totally color blind, they've no business being an electrician, and should call for some help.
 
WDeanN said:
The same way anyone else would!

Most colorblind people are red-green or blue-yellow color blind.
If they are totally color blind, they've no business being an electrician, and should call for some help.
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Chicken !
 
I would truly like to answer, but I have never in my life used, or needed to use a 2-lead neon tester, I have always relied upon the FLUKE line of meter products.:grin:
 
But that is not the point:

But that is not the point:

kingpb said:
I would truly like to answer, but I have never in my life used, or needed to use a 2-lead neon tester, I have always relied upon the FLUKE line of meter products.:grin:
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Fluke is fine, but for a quick diagnosis, the little neon tester can tell a lot, and they fit one's shirt pocket better than a VOM. My first one cost 29 cents
 
Even a colorblind electrician would know better than to work with live wires. And without power, the neon tester by itself could not give you any useful information.

So my best bet would be to offer to give the tester to the owner, as a free prize, if the owner agreed to tell me what type of power system was installed. If that didn?t work, I might consider forcing him to tell me what I wanted to know, by threatening to stick the tester in his eyes if he refused.
 
rattus said:
Fluke is fine, but for a quick diagnosis, the little neon tester can tell a lot, and they fit one's shirt pocket better than a VOM. My first one cost 29 cents
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Ah-ha, that's the difference, I don't have a pocket protector to stick it into, that must be why I never had one........
 
How could you?

How could you?

charlie b said:
Even a colorblind electrician would know better than to work with live wires. And without power, the neon tester by itself could not give you any useful information.

So my best bet would be to offer to give the tester to the owner, as a free prize, if the owner agreed to tell me what type of power system was installed. If that didn?t work, I might consider forcing him to tell me what I wanted to know, by threatening to stick the tester in his eyes if he refused.
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How can you measure anything if the wires are dead?
 
rattus said:
How can you measure anything if the wires are dead?
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You don't. That was my point. That is also why I would resort to bribery or intimidation, in order to get the owner to tell me the answer. :wink:
 
All right, since I've been called out, I'll answer:

3-ph delta service will light the tester on all 3 leads, wire to wire, but not each wire to known ground.

3-ph wye service with a missing neutral will light on all wire to wire, as well as each wire to known ground.

1-ph 120/240 service will light between all 3 wire to wire, and one wire (neutral) will not light to ground.

3-wire 2-ph service - not sure how this would differ from above.

Edited to correct last two after some thought:

1-ph 120/240 service will light one wire to other two and to ground, but other two will not light to each other, or to known ground.
3-wire 2-ph service will light between all 3 wire to wire, and one wire (neutral) will not light to ground.
 
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In my experiece the neon tester will light when touching one lead to the conductor and holding the other in your fingers. This was a very common method used to identify the ungrounded conductor of knob and tube system. I would expect that the tester will light from the ungrounded conductors to the grounding conductor on both the delta and wye systems.
Don
 
I would only hire a neon tester that wasn't color blind because the retail stores are very sensitive to the color tones on their signs. After he told me the colors I would have him fetch the prints from the cabinet.
 
I think the neon tester thing is to throw you off track, The color blind electrician

would follow the circuit back to it's source and read the nameplates on the

supply equipment, then he would turn the circuit off so he would not end up

a totally blind person.
 
I had a color blind apprentice for a while. I can't remember which way he was color blind, but it turned out that he was able to overcome his color blindness with a colored flashlight ( at least for low black red blue white).
 
Rewire said:
What about the 3 Phase with a grounded phase
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I think any service with a grounded conductor would be difficult to identify with the neon tester. Time to get out the $10 meter which you can afford to lose.
 
don_resqcapt19 said:
In my experiece the neon tester will light when touching one lead to the conductor and holding the other in your fingers. This was a very common method used to identify the ungrounded conductor of knob and tube system. I would expect that the tester will light from the ungrounded conductors to the grounding conductor on both the delta and wye systems.
Don
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I think that on the delta you might see a dim and perhaps uneven light from the neon. On the wye, we know we would see a bright, even light on all three phases to ground. Don't have access to delta, so I can't test it.
 
No question that the neon tester is rather limited, however, if one knows the nature of the service, it can be useful. Of course a real electrician would carry a decent VOM on a call.
 
Worked with a color blind electrician once. I had run almost all the EMT in this warehouse/shop and the boss sent him to give me a hand. All he asked me was, "Is this dark gray one the Red or the Green"? (He could tell which was the Black & Blue.) I said that it was the Red and the Green was a light Green. He pushed all the short runs and I finished the EMT home runs. We flipped on the power and there wasn't any sparks!
 
charlie b said:
Even a colorblind electrician would know better than to work with live wires. And without power, the neon tester by itself could not give you any useful information.

So my best bet would be to offer to give the tester to the owner, as a free prize, if the owner agreed to tell me what type of power system was installed. If that didn’t work, I might consider forcing him to tell me what I wanted to know, by threatening to stick the tester in his eyes if he refused.
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That had me laughing. Perhaps 1 tester lead in each eye?

~Matt
 
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