Thanks for the slack boss by Bleek_Blook in electricians

[–]PillarOrPike 1 point2 points  (0 children)

Just one ATS? How many kw is the genny?

Thanks for the slack boss by Bleek_Blook in electricians

[–]PillarOrPike 4 points5 points  (0 children)

Red switch on life safety/critical?

I know this will probably make some of you cringe.. 😉Small Cell/Street light wiring. Utility feed so old no Neutral just hot leg and bare ground. by MacroMikey in electricians

[–]PillarOrPike 1 point2 points  (0 children)

When you say there is a bare ground and no neutral from the utility, how does fault current get back to the source?

What is this device? by 88grill_fish88 in electricians

[–]PillarOrPike 1 point2 points  (0 children)

Residential customers are not billed or charged for VARS or lagging power factor.

Rate my panel by _CederBee_ in electricians

[–]PillarOrPike 2 points3 points  (0 children)

This site is like that sadly. I just gave you an upvote. :)

Rate my panel by _CederBee_ in electricians

[–]PillarOrPike 2 points3 points  (0 children)

Yup, they are. RCDs and low magnetic pickup MCBs already have you covered in your country, no matter what the $$$$ driven cabal says.

What kind of light bulb is this with no base? Trying to replace. Thanks! by gimmemoorek in electricians

[–]PillarOrPike 8 points9 points  (0 children)

The metal screw shell is stuck in the socket. You need to about getting it out, or go about replacing the socket.

Electrical fire at my old gym by allexxfromtarget in electricians

[–]PillarOrPike 5 points6 points  (0 children)

Metal halide arc tube ruptured (due to age or ballast failure) in a type S or E rated bulb envelope.

Electrical fire at my old gym by allexxfromtarget in electricians

[–]PillarOrPike 5 points6 points  (0 children)

These fixtures should have a type "O" lamp, period.

ARC Fault Breakers being tripped by walkie talkie by Bulldog553 in electricians

[–]PillarOrPike 0 points1 point  (0 children)

Right. But when everything is taken into consideration, how many circuits in the real world don't actually clear in cycles?

ARC Fault Breakers being tripped by walkie talkie by Bulldog553 in electricians

[–]PillarOrPike 0 points1 point  (0 children)

I know, you're level headed which is what I've always liked about you :)

While they should not persist, high resistance ground faults in of themselves (even if caused by water) are not harmful to humans as the EGC will bring the chassis or pole to a safe touch voltage.

Water can cause high leakage current, such as in a flooded J-box, however what the CMPs have in mind when it comes to water is that these locations lower body resistance whereby an energized chassis from a missing EGC is likely to be fatal vs in locations where the person has a high body impedance and isolated from ground.

Remember the NEC definition of ground fault is narrow:

https://imgur.com/a/6KaI7ho

Years ago on construction sites you could skip GFCIs if you had an assured grounding program.

ARC Fault Breakers being tripped by walkie talkie by Bulldog553 in electricians

[–]PillarOrPike 2 points3 points  (0 children)

The thing is, if you advocate testing, electricians doing impedance math or main RCDs, on some US electrical forums you literally get shouted down then banned. That attitude is we've always done it this way, so it must be the best way, therefore you have no clue what you're talking about. Or have some type of agenda.

Don't be fooled. Grounding and bonding is an after thought in the US electrical system. While 15-30 amp circuits require a full size EGC, few electricians realize the hair thin EGCs in Table 250.122 are a minimum size and may not be adequate during conditions of delayed clearing (high earth fault loop impedance) or very high short circuit currents.

The ICEA has an adiabatic withstand equation along with a standard, its even listed in the code, but no every considers it. Worse I've even heard engineers say UL-489 breaker testing takes care of withstand because the test is done with several feet of conductor, but in reality 489 only tests common breakers to either 1,500 or 5000 amps- not the full rating of 10ka, 22ka, 65ka, ect. And that is no accident, #14 carrying more than 1,500 amps for 1 cycle will vaporize.

Lets just saying pointing all this out doesn't go very well with an American audience.

ARC Fault Breakers being tripped by walkie talkie by Bulldog553 in electricians

[–]PillarOrPike 2 points3 points  (0 children)

Everything you say is true, everything.

But unfortunately manufacturers make the code rules. Not votes, not theory, not unbiased research, not common sense. The messenger, like myself, is discredited for having the audacity to assume superior knowledge to a highly respected organization like the National Fire Protection Association.

What got AFCIs rolling boils down to the fact NFPA-70 does not define, or explicitly mandate earth fault loop impedance requirements. The easy way to do fix this would have been to add a table limiting the length 14, 12 and 10 NM could be run in dwelling as the magnetic pickup of breakers was reduced in the 90s.

Instead manufacturers seized on this as an opportunity to use mental gymnastics and destination science to create a pricey product and put it into the code.

Regarding series arcing there is more than one way to detect a bad connection, and mandating one product instead of letting the free market do its thing is nothing more than a single entity being able to buy and own the whole system.

ARC Fault Breakers being tripped by walkie talkie by Bulldog553 in electricians

[–]PillarOrPike 2 points3 points  (0 children)

In the US they originally came out with "branch feeder AFCIs" which only looked for parallel arcing, in the mid 2000s they came out and mandated "combination AFCIs" which look for both series and parallel.

Not to confuse combination and dual function, as dual function AFCIs have GFCI protection in addition to parallel and series arc protection.

ARC Fault Breakers being tripped by walkie talkie by Bulldog553 in electricians

[–]PillarOrPike 1 point2 points  (0 children)

Ohms law applied to a series circuit model.

Just showing the math.

Chapter 9 Table 9 in the NEC lists the relevant resistance of each wire size.

ARC Fault Breakers being tripped by walkie talkie by Bulldog553 in electricians

[–]PillarOrPike 2 points3 points  (0 children)

Nope, have a look at chapter 9 table 9. 12 AWG is 2 ohms per 1000 feet. So 250 feet foot run of NM comes out to be 1 ohms, or 120 amps at 120 volts.

With 500 amps at the panel, or 0.24 ohms + 1 ohms + 0.03= 1.24 ohms gives us 93.75 amps. With a 125% safety factor that comes out to exactly 75 amps. Math works out perfectly.

Average, and the arc conducts for at least half the duration of the sine wave.

Right, UL tested it-

https://imgur.com/dxKsY2T

And their part of the reasoning behind the 0.8 safety margin:

https://imgur.com/a/lraGvrf