Electric Meter for Black Outs?

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I recently hooked my generator into the main box, with a lock-out device of course. If the power goes out, I'll turn off the main switch to the street manually and flip to generator power.
The problem is how to know when the street power is back on, other than loo king down the street to see if the neighbors have lights on again. When I j ust ran extension cords from the generator to the well, refrigerators, etc. , during an outage, when the power started up again various lights would li ght up around the house as they had been on and were still street-connected . Now, everything is disconnected from the street.
It would be nice if there were some sort of induction device I could clamp on the main line coming in from the street which would light up an LED if t here were power in the line, but if there's no current actually flowing I d on't see how it would pick up the potential voltage in the line. Is there s uch a thing available or will I have to invent one?
Paul
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Pavel314 wrote:

I don't know if it is good enough for your purpose. Sniff-it 2 by Triplett can sniff and beep or light up an indicator. Take a look.
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On 12/12/2013 04:27 PM, Tony Hwang wrote:

My thought exactly, except I'm using a similar Sperry branded product. (the Triplett had excellent reviews, but as I recall it uses odd batteries - CR2 I think? - whereas the Sperry uses standard AA or AAA cells.)
However, it will probably only work if you check the individual conductors inside the breaker box however as the braid in a service entrance cable may prevent a NCVD from working, and if it's in metal conduit, fuhgeddaboutit.
At that point, a test light is just as useful...
nate
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"Pavel314" wrote in message
I recently hooked my generator into the main box, with a lock-out device of course. If the power goes out, I'll turn off the main switch to the street manually and flip to generator power.
The problem is how to know when the street power is back on, other than looking down the street to see if the neighbors have lights on again. When I just ran extension cords from the generator to the well, refrigerators, etc., during an outage, when the power started up again various lights would light up around the house as they had been on and were still street-connected. Now, everything is disconnected from the street.
It would be nice if there were some sort of induction device I could clamp on the main line coming in from the street which would light up an LED if there were power in the line, but if there's no current actually flowing I don't see how it would pick up the potential voltage in the line. Is there such a thing available or will I have to invent one?
Paul
Simple. Use induction method. Like a clamp amp meter works. To light your LED
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wrote:

A clamp meter detects CURRENT - and there is none without a load. I'm thinking about a neon indicator connected to the line side of the main switch.
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wrote in message

Snip>

A clamp meter detects CURRENT - and there is none without a load. I'm thinking about a neon indicator connected to the line side of the main switch.
In commercial high use of power a current (transformer) in line with the load. Referring to high amps usage. 400, 800, 1000 or more. A copper bar is wrapped with coils of small wire. This produces a voltage the is connected to a normal utility electric meter (like one on your house) this is then measured indicating usage divided by the amp size of the current transformer. So a few turns of wire around the line wire can produce a small voltage. There Must Be a load current in the line wire for this to work. I will try to come up with a practical setup and get back to this site. WW
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On 12/12/2013 3:12 PM, Pavel314 wrote:

Years ago, I installed some taps for roadies to hook up lights for the stage in a night club. To let them know that the power was on the box at the end of the conduit, I installed a neon pilot light for each phase. In your case, you can get voltage sensors that can be wired to an alarm or flashing indicator light to let you know when your main power comes back on or just wire up a standard wall light or an exit sign with your own panel reading "POWER". ^_^
TDD
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The Daring Dufas wrote:

Along those lines I installed a pair of neon indicators mounted to a metal box cover, installed in a metal electrical box and connected to my panel with a metal offset nipple. They are connected to the input side of the main breaker directly, being ~18ga wire and enclosed in metal enclosures if something fails they are self fusing and can't start anything on fire. I use an interlock kit for the generator connection (Square D kit in a Square D panel).
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"Pete C." wrote:

I should add that I made those connections while I had the meter pulled in the process of replacing my panel. I don't recommend anyone but the most experienced make those connections with the panel live, and certainly not under load.
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On 12/12/2013 05:49 PM, Pete C. wrote:

That sounds like a good idea, and probably what I would do were I trying to do something like this myself, I just wonder if it's code compliant?
Also, at what voltage do the neon indicators light up? e.g. will they glow if there's say 10V on the line?
nate
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On 12/12/2013 4:56 PM, Nate Nagel wrote:

Most standard neon pilot lights have a dropping resistor built into the holder or base and are suitable as a power indicator for any 120vac or 240vac source. The neon pilot light needs at least 90 volts to light if I'm remembering correctly. ^_^
TDD
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Nate Nagel wrote:

I'm not sure on that, code mostly is concerned with fire risk, and when enclosed in all metal conduit and box the heat produced in the mS it takes to vaporize an 18ga wire at fault currents couldn't possibly set anything outside the enclosure on fire.

A quick look on Digi-Key seems to indicate a 105-125VAC rating on many indicators. I don't see a clear indication that 105VAC is the threshold, but I expect it's not too far below that. For more $ you could install basic panel meters, and probably inline fuses on them, though I'd still use the indicators as well since you can check them from a distance to see if utility power is back.
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On 12/12/2013 5:10 PM, Pete C. wrote:

I always put an inline fuse holder on the power feeding the indicators and install a 1 amp or smaller fuse.

I seem to recall 90vac as the lowest voltage that will light one of those small neon pilot lights. ^_^
TDD
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The Daring Dufas wrote:

I thought of that, however I considered that the cheap in-line fuse holders would present a greater risk when one side is always live. I think just letting a fault vaporize the wire is safer than potentially having someone try to replace a fuse and pulling it out bare fingered from a live fuseholder.

Sounds familiar to me too.
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On 12/12/2013 8:34 PM, Pete C. wrote:

Using a glass fuse holder like the Littelfuse model 155 Series Twist-Lock In-Line Holders for 3AG Fuses is a safe way to because you can tie a knot in the pigtail wire on each end to keep the wire up in the fuse holder. I do that if I don't have any small cable ties to wrap around the wires to keep them from slipping out of the insulated cap. The twist-lock in-line holders are safer than the 155 Series Heavy-Duty Bayonet Knob In-Line Holders because there is no exposed metal when the fuse holder is opened.
http://www.littelfuse.com/products/fuses/passenger-car-and-commercial-vehicle/fuseholders/155100.aspx
http://www.littelfuse.com/products/fuses/passenger-car-and-commercial-vehicle/fuseholders/15500.aspx
The problem with your fuse-link wire is if it melts, the wire could touch the metal housing if the insulation burns off. You could your fuse link inside some fiberglass sleeve like what is used to insulate electric motor lead wires. It's heat resistant and the burned wire will not burn through.
http://www.essexbrownell.com/tubingandsleeving.aspx

I have years of experience shorting out and burning up electrical and electronic stuff when I've done my mad scientist like experiments with electricity. ^_^
TDD
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On 12/12/2013 7:13 PM, The Daring Dufas wrote:

Some utility meters have LEDs that indicate there is power. A 'non-contact' voltage tester might indicate if held next to the meter in the right spot. I don't know of a simple method other than that I would use to show the power is back on.

So what happens if the #18 wire acts as a fuse? There are a few thousand amps fault current available at the service. A fault of a few thousand amps through #18 wire will continue an arc over a rather long distance. And what will happen with the 'spring' in the wire - where will the wires go when they are broken at the arc?

Nope.

It is a rather different case. But downtown there was a maybe 8 story building that had a fire. They tore it down to the first floor and basement, installed a ramp, and used what was left as a parking lot. The original service remained (208/120V), far larger than needed, with 6 parallel sets of service wires. They cleverly stored salt for the ramp on top of the service switchgear. The service wound up with an arc-fault and burned down. Some of the service wires burned back into the supply conduits. Some of them were live in the conduit. Some wires welded to the conduit and the utility couldn't pull them out with a comealong. (The wires were protected by "cable limiters" at the utility transformer vault.

So what happens if there is a large fault current through the fuse? Like the wire, with high current the arc continues and the fuse and fuse holder blow up. Fuses have a rating for available fault current. In most applications on a branch circuit you don't think about it. When you have high fault currents available you have to (and are required to by the NEC).
[The fuses included in some Fluke meters are rated for high fault currents and the meters have a "category" rating for use where there are high available fault currents.]
Is a problem likely? Don't know. But I wouldn't connect anything to the service wire terminals.

NE-51 (bayonet base) and NE-2 (wire lead) are common neon pilot lights. They trigger on at about 65V (and would be used at a higher voltage). Neon lamps must have a series resistor which is built into the assemblies above.
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On 12/13/2013 11:37 AM, bud-- wrote:

Bud, I think you may have been responding to the wrong poster but your thoughts are welcome. ^_^
TDD
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bud-- wrote:

If an arc is maintained on the 18ga wire it won't be for long. Ultimately it will burn back to extinguish the arc in a matter of milliseconds. Either way there is no chance of it starting a sustained fire in my house. Safety wise it's not much different than a wire nut coming loose, something that happens from time to time.

No code requirements here so I don't care.

Do a test with 18ga wire connected across even a 100A breaker, much less a service drop limited only by the transformer and see if any of the wire is left. My assessment is that installing any kind of replaceable fuse presents more of a hazard than the non-replaceable fuse-link the wire presents.

Every single automatic transfer switch connects monitoring to the utility service. It's a total non-issue, much like 3D printed guns.

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On 12/13/2013 11:56 AM, Pete C. wrote:

Many vehicles have a fuse link inside a thick heat resistant silicone rubber jacket. When the wire melts, it doesn't penetrate the insulation so it's very safe. You can make your own safe fuse link with #18 wire by putting it inside some braided fiberglass insulated sleeve like what is used inside electric motors or appliances with electric heating elements. ^_^
http://www.electroinsulation.com/extruded-tubing-and-sleeves/fiberglass-electrical-sleeving.html
http://preview.tinyurl.com/ojf2x7h
TDD
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On 12/13/2013 11:56 AM, Pete C. wrote:

Time depends on fault current, wire 'spring, magnetic effects.

You don't have thousands of amps available at a wire nut.

I have seen videos of using the wrong meter in a high capacity disconnect where the meter lead failure propagated to an arc-flash. That started with 'none of the wire left'.

Part of a listed device, and not likely unprotected #18 wire connected to service wires.
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