National Electrical Code --- Electricians are Special People

[rockmeupto125]

*The general rule of thumb is that circuit breaker size should be 125% of the ampacity of cable and wire or the circuit which has to be protected by the CB.

 

So if my wire is rated at 65 amps, I should use an 80 amp breaker.

 

*but NEC suggests 80% as a safe current limit as compared to the rated current of CBs.

 

80% of 80 is 64 amps. The next highest industry standard is 70 amps.

 

So I use a 70 amp breaker on my 65 amp rated wire with a calculated load of 52.5 amps. ARRRGGGG.

 

I've used the lights, compressor, and welder on a 30 amp circuit with 10 gauge wire for the last 12 years, and only tripped a breaker once with a ground contact on a receptacle that hadn't been replaced after the flood.

 

The temptation is there to use a smaller wire than I had originally intended for my planned 60 amp service.

 

But it's not that much more $$ to just go ahead make it an 80 amp service. 

[SwampNut]

Anything worth doing is worth over-doing.

 

[Zero Knievel]

3 hours ago, SwampNut said:

Anything worth doing is worth over-doing.

 

That was dad's philosophy.  Of course, it makes sense in that you don't worry about overrunning the capability of your setup if it's set to handle more than you will use.

[XXitanium]

...more power!

 

https://youtu.be/KYsu5ZmL214?si=va_gDzRUIQoROsGF

 

 

 

Edited December 21, 2023 by XXitanium

[SierraKLR]

The issue is that most circuit breakers are labled at their free air rating or handle rating.  The moment you put the in an enclosure or any type NEC requires a 20% defraying due to ambient heat.  Hence the 20% derating

 

Wire is tested and labeled at it’s 90 degree C rating, but NEC requires that it be sized ,for load purposes, at it’s 70 degree C rating 

[XXitanium]

...

Edited December 21, 2023 by XXitanium

[SwampNut]

Hey, what do you guys call those non-contact AC detectors that make a warbling noise?  I used my term for it around East coast people and they looked at me like I'd grown a third arm.

 

[ironmike]

Um, AC voltage detector? At least that's what the label on it's side reads (Craftsman model). I can't remember hearing another term for it.

[SwampNut]

Wiggy.  Although it's the trade name for a very early contact-type meter, I've heard the term many times in reference to the non-contact.  If you google it, you get what you expect and also contact meters.  In any case, I'd never do any high voltage work without one.

 

 

 

 

[XXitanium]

I had jiggler in my head. Some random on the web agreed with me. I had a couple different makes in my time.

 

[SwampNut]

Ask an AI...

 

Answer
In electrician parlance, a "Wiggy" refers to a specific type of voltage tester known as a solenoid voltmeter. It is a durable, simple device with two test leads connected to a solenoid coil inside a plastic casing. The Wiggy has an indicator bar attached to the solenoid that moves to show voltage levels when the device is connected to a circuit. It can test both AC and DC voltages and also indicate the polarity of the current. The Wiggy is known for its durability, ease of use, and the ability to give a general approximation of voltage rather than an exact value. It is particularly useful in fieldwork due to its stability and the distinct sounds it makes—a loud click for DC and a buzzing for AC—when connected to a power source
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A "jiggler," on the other hand, is a term used to describe a secondary voltage tester, also known as a glow light. It is a simpler device compared to the Wiggy and is used for detecting the presence of voltage. The term "wiggle" is also associated with this type of tester and is sometimes used interchangeably with "jiggler"
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Both tools are commonly used by electricians for different purposes: the Wiggy for more robust voltage testing and the jiggler for a quick check of voltage presence.

[XXitanium]

Hmm, I thought the devices came in differing ranges. We did some work at decent sized transmission stations. It's been over 10 years.

[SwampNut]

2 minutes ago, XXitanium said:

Hmm, I thought the devices came in differing ranges. We did some work at decent sized transmission stations. It's been over 10 years.

 

The non-contact detectors?  They do.  Or at least, mine specifies a range.  I just tried mine on 24VAC and it was very unreliable.  You have to hold a certain part of it right on the wire (full contact).

[OMG]

Just use your finger, just a light tingle as long as your thumb is on a ground first.😋

[superhawk996]

I assume there's no danger in running a wire that's bigger than the breaker's rating and that the 125% thing is to allow using all the juice that the wire can give.  Voltage drop is your enemy.  I learned the hard way that when I connect to outlets that are farther from the panel my welder's limit decreases dramatically.

 

If your projected needs are anywhere near the edge of XX size wire, go up one.

[SwampNut]

There's no danger, and I assume it must be legal because many houses have 20a-rated wire and they put in 15a breakers.

 

[rockmeupto125]

The purpose of the breaker (OCPD, over current protection device) is to protect the wire.

 

It may not be necessary, but I plan to upsize the wire as much as I can. It's analogous to putting 16 ply tires on a 2 place motorcycle trailer. You can do it, but it's not needed. Sizing up the wiring will cost another $100. The tires would cost lots more.  And unlike the tires, I'm only going to do this once.

[SwampNut]

The tires would actually have a downside though, in bouncing instead of flexing.

 

[JaBr]

On 12/21/2023 at 3:29 PM, SwampNut said:

Hey, what do you guys call those non-contact AC detectors that make a warbling noise?  I used my term for it around East coast people and they looked at me like I'd grown a third arm.

 

Warbler here in the UK