Electrian dad says GCFI is pointless? - Page 9

The Pol · 02-10-2010, 01:07 PM

I am using a 50A GFCI CB so that I dont get yelled at.

**CodeRage** · 02-10-2010, 01:52 PM

Quote:

Originally Posted by Hullguy

I agree with your dad on the 240v elements. You need a neutral to trip a GFCI and your elements don't have one!

A GFCI will work with out a neutral..... It's all about current in vs current out.

Hermit · 02-10-2010, 03:15 PM

Quote:

Originally Posted by CodeRage

A GFCI will work with out a neutral..... It's all about current in vs current out.

How do you differentiate current in vs out on a 240 circuit since both sides supply current? Many home appliances that use 240 also have 120 components. I've done amperage readings on dryers and there is a difference in current on the leg that has the motor. I can hardly wait for the people that build the GFCI's to get them mandated for all home appliances.

**CodeRage** · 02-10-2010, 03:37 PM

Quote:

Originally Posted by Hermit

How do you differentiate current in vs out on a 240 circuit since both sides supply current? Many home appliances that use 240 also have 120 components. I've done amperage readings on dryers and there is a difference in current on the leg that has the motor. I can hardly wait for the people that build the GFCI's to get them mandated for all home appliances.

in 120V current goes back and forth between neutral and 120V, hence alternating current. if the current leaving L1 is equal to the current flowing through N and vice versa there is no ground fault.

240V is the same thing. Current flows back and forth between L1 and L2, as long as #mA is measured leaving L1 and is flowing #mA into L2 there is no ground fault. When they are out of balance current is going somewhere else and the gfci pops.

They make 2 pole GFCIs that support split phase as well. You can identify them by the curly white pigtail attached to them. They monitor all three, L1, L2, and Neutral and if any current is unaccounted for it pops.

mhermetz · 02-10-2010, 05:23 PM

.....crap I totally need to re-build my chiller.

I can slip it in the boilmaker easily but once the elements are in the chiller it will be sitting 2 inches above the wort level. Unless I can some how slip the chiller under the elements too.

Not entirely bad... but not as effecient as it could be.

**CodeRage** · 02-10-2010, 05:25 PM

Quote:

Originally Posted by mhermetz

.....crap I totally need to re-build my chiller.

I can slip it in the boilmaker easily but once the elements are in the chiller it will be sitting 2 inches above the wort level. Unless I can some how slip the chiller under the elements too.

Not entirely bad... but not as effecient as it could be.

Thats why I went CFC. Or you could make a fixed mount IC in there that bends around the element.

mhermetz · 02-10-2010, 06:07 PM

I could do that.... Think I would be able to roll out the copper tube without weakening or causes kinks? I assume you have to do that to make the CFC

abracadabra · 02-10-2010, 06:57 PM

Quote:

Originally Posted by Randar

You're not talking about a 60W light bulb. You're talking about 30+ amps of continuous peak current, which is PLENTY to kill you.

Oh, and I have seen enough misconceptions of electricity in this thread to warn a few of you to not do your own electrical work...

Speaking of misconceptions "30+ amps of continuous peak current"

240v AC (Alternating Current ) goes from 0v to 120v back to 0v then to 120v in the opposite direction or polarity for a total swing of 240v. The current goes up and down with the voltage and the electrons changes the direction in which they flow as the voltage changes polarity.

DC (Direct Current) can offer a continuous peak current.

Or you'd need something like 3 phase AC to be close to a continuous peak current condition.

Residential electricity is single phase AC.

Jknapp · 02-10-2010, 07:11 PM

Interesting situation happened at work, that sorta applies to the Murphy's Law/GFCI thing..

On a job site, a extension cord (we call em stingers) was plugged into a 20amp GFCI outlet on a 20A circuit. A tech mistakely cut the plugged-in extension cord with his linemans pliers. POP! After making sure he was okay, we went to reset the GFCI - but it wasn't tripped. Went to the panel & the 20a breaker was what tripped.

Hmm. The GFCI was wired correctly: wires to panel feed the Line side. GFCI tests fine.

Our theory: as his pliers cut through the 12/3 cord, his cutter first severed the hot & ground first, cutting the neutal after the panel breaker popped. That's our theory, but in any case the GFCI, which is supposed to be sensitive, didn't do anything.

Anyway, moral of the story: Things sometimes don't go the way we want or expect. GFCI's are great things, even if they don't ALWAYS provide protection. Oh, and Murphy's Law is always in effect.

**CodeRage** · 02-10-2010, 07:12 PM

Quote:

Originally Posted by abracadabra

Speaking of misconceptions "30+ amps of continuous peak current"

240v AC (Alternating Current ) goes from 0v to 120v back to 0v then to 120v in the opposite direction or polarity for a total swing of 240v. The current goes up and down with the voltage and the electrons changes the direction of it flows or with the change of voltage polarity.

DC (Direct Current) can offer a continuous peak current.

Or you'd need something like 3 phase AC to be close to a continuous peak current condition.

Since the voltage is rated at RMS saying the current is continuous peak at I RMS is perfectly acceptable...