arc fault ghost

[Fulthrotl]

not yet... i printed out the letter, and have to get a rma, and send it in.
for my model number, and serial number, there is no charge for the upgrade.

wonder if the firmware upgrade would allow it to measure the current in
the branch circuit.... hmm.... we can only hope.....

just got my RMA# from ideal. no charge for the upgrade,
and the increased functionality of being able to measure
current flow in the circuit tested from any point in the circuit
should be included with the firmware upgrade.

life is good.

 

[ohm]

Why would you say that?
You read 75 amps in all publications I have seen. I have never seen them specify "peak" . If no qaulifier is made I usually understand it to mean average or RMS.

Here is one link that specifically says 75A RMS.

www.eaton.com/ecm/idcplg?IdcService=GET_FILE&dID=69015

I do not have access to UL1699 but that should be the definitive.

Besides that does not matter in terms of what I posted about the SureTest upgrade. Either way the device would not trip if the line impedance was too high. So surely they encountered issues in the real world where the line impedance was too high.

True they all say 75A and we all know if not qualified that means RMS. But the C-H powerpoint page #13 reads a little funny; "It recognizes the signature of parallel arcing faults in (2-wire or 2-wire plus ground) circuits with AVAILABLE FAULT CURRENTS of 75 amps (*) rms and interrupts the circuit.

I've looked all over their presentation for the definition of the (*) to no avail. Do they mean if 10Kaic RMS is available at the pole will it trip if at least 75A RMS is available at the AFCI or the fault? That sounds like a given.

Finally, if the shure test can trip the AFCI on Arc Fault (not GFCI) is it actually loading down the circuit 75A RMS through it's cord? How long would that hold up?

And, you're right if the fault Z was too high.

 

[Pierre C Belarge]

how do you terminate that stranded wire under the green screw on the receptacle without violating the listing?

most (not all) 15 and 20 amp 120/277 volt devices arent designed to terminate stranded wire under the green screw...

Where did you get this information from?
Take a peek at the UL White book, it specifically states that terminating stranded conductors to screw terminals is permitted.

 

[ELA]

I've looked all over their presentation for the definition of the (*) to no avail. Do they mean if 10Kaic RMS is available at the pole will it trip if at least 75A RMS is available at the AFCI or the fault? That sounds like a given.

Finally, if the shure test can trip the AFCI on Arc Fault (not GFCI) is it actually loading down the circuit 75A RMS through it's cord? How long would that hold up?

And, you're right if the fault Z was too high.

Ohm,

I do not know what the (*) is supposed to mean and could not locate it either.

I surely would expect the SureTest to load the circuit to 75 or more amps.
This load only has to last long enough for the AFCI to detect it. In one document I read that was a minimum of 5 half cycles.

There are many pieces of equipment that draw large currents for a short duration through normal 15-20 amp circuits, like vacuum cleaners.
Cords handle this just fine.


I have been curious as to what the time/current curve for these AFCI's might look like as I have never seen one presented (in terms of the AFCI detection portion)? From what I have read it probably varies based on several variables , 60Hz RMS current, High Freq. levels present, etc.

 

[ohm]

Ohm,

I do not know what the (*) is supposed to mean and could not locate it either.

I surely would expect the SureTest to load the circuit to 75 or more amps.
This load only has to last long enough for the AFCI to detect it. In one document I read that was a minimum of 5 half cycles.

There are many pieces of equipment that draw large currents for a short duration through normal 15-20 amp circuits, like vacuum cleaners.
Cords handle this just fine.


I have been curious as to what the time/current curve for these AFCI's might look like as I have never seen one presented (in terms of the AFCI detection portion)? From what I have read it probably varies based on several variables , 60Hz RMS current, High Freq. levels present, etc.

The (*) explaination was probably edited by the trade secret guys.

After twenty 5 half cycles of 75A RMS even a #12 cord might get a little curl in it. I wonder what size cord the shure-test uses?

A 1000 W incandescent lamp typically draws 100A for the first two 1/2 cycles if the lamps are cold & the switch is closed at the top of the sine wave...not good for an ordinary SP switch. According to Siemens if the current stays above 75A for five 1/2 cycles, it's considered an arcing fault.

I suspect it's a balancing act to get a good test and stay under the time/current curve of a 20A breaker, especially if the breaker has been zapped a few times in the last 5 min.

 

[lbwireman]

I haven't taught in a few years and haven't used a sure test yet but I'm inches away from getting one. $280 is about the best price I've found and another $100 for case,leads etc.

I've gotten by with digital multimeters, meggers, earth testers large loads and wiggies so far but from what I'm reading the sure test seems like a time saver...what say you?

Here ya go:grin:

 

[ohm]

Here ya go:grin:

Thanks for the info LB. In looking around I'll probably go w/ the 61-165 which can do a little more than the 61-059

 

[lbwireman]

not yet... i printed out the letter, and have to get a rma, and send it in.
for my model number, and serial number, there is no charge for the upgrade.

wonder if the firmware upgrade would allow it to measure the current in
the branch circuit.... hmm.... we can only hope.....


randy

Is the letter on this page the one to which you refer? It appears that the 165 model is the one that would be wanted (AFCI testing and all) but I don't see anything on the list of features that leads me to believe it would measure current other than the ability to apply a simulated load to test for voltage drop (my old Tasco Inspector II does this with "idiot lights"). Where did you hear of a model that would measure current?

Sean

 

[lbwireman]

Never Mind

Never Mind

Just got to your post # 41. Ignore my previous post.

 

[wptski]

The new Ideal 61-165 ELL feature.

Instruction for use of Estimated Load on Line

The IDEAL SureTest models 61-164 and 61-165 have now incorporated an Estimated Load on Line (ELL) feature. This function allows the user to quickly obtain a general idea of the total current load drawn on the branch circuit. The proprietary way in which these calculations are made allows the user to plug the unit into an outlet and measure current load on that branch circuit.

Best accuracy can be obtained by becoming familiar with the operation of the load on line test. The distance of the SureTest from the load will affect accuracy. Try to position the SureTest close to the largest load on line.

For best accuracy, power up all loads and make certain they are working at their normal rate of operation, then plug the SureTest into an appropriate
nearby outlet on the same circuit. The Load on Line will be very close to
the actual load. The maximum current measured is held in the small display at the top right hand corner. This value will be held until the Sure Test is removed from the outlet.

While you may do so, the accuracy will suffer if loads are turned on and off during the test period. To quickly confirm a questionable reading, remove the SureTest and reinsert it to recalculate with all loads running.

Due to the proprietary method used to calculate the load, variations in the line and neutral resistance can cause significant variations to the accuracy of the displayed current. Ideally, there should be less than 5% Vd and less than 0.25 Ohms of resistance. In cirical applications, it is recommended that a traditional current clamp such as the Ideal Model 61-746 be used at the panel to obtain a very accurate current measurement.



ESTIMATED LOAD ON LINE.

The estimated load on line (ELL) is limited to a maximum reading of 15 amps, to best reflect actual conditions on the line as the data is monitored. The Peak Hold display will monitor the load as long as the SureTest is plugged into the outlet. It indicates an estimate of the maximum load on that circuit over time. The calculation is based on the
peak current flowing in the neutral conductor. Neutral current is the
result of powered equipment on the line. The ELL will also help indicate circuits that are overloaded, and those that have a common neutral. This is especially important when the circuit being measured powers single phase switching power supplies, like computers. The third harmonic generated by this equipment is not cancelled, and returns on the neutral, causing overload and heating of the neutral conductor. This is particularly true in 3 phase 4 wire panels, (120/208) where third harmonic is very common. The test allows determination of the remaining capacity of the circuit. It can also help determine whether or not the circuit is dedicated, since a circuit with no load will have very low or zero neutral to ground voltage. Any reading over 1 amp indicates the circuit is very likely not dedicated.

The load on line is strictly an estimate. This is an indirect reading, so there may be significant error in the reported values.

The SureTest does not have to be in the furthest outlet on the branch circuit. Accuracy will decrease significantly with distance. Worst accuracy will result when the load is between the SureTest and the distribution panel.

To get the very best results, the SureTest should be plugged into the same outlet as the load, with no other loads on line.

Remember that shared neutrals will indicate the current flowing from both hot wires. If the ground wire is carrying current, there will be significant error introduced, and this is a dangerous situation that should be rectified immediately.

 

[ohm]

The new Ideal 61-165 ELL feature.

Instruction for use of Estimated Load on Line

The IDEAL SureTest models 61-164 and 61-165 have now incorporated an Estimated Load on Line (ELL) feature. This function allows the user to quickly obtain a general idea of the total current load drawn on the branch circuit. The proprietary way in which these calculations are made allows the user to plug the unit into an outlet and measure current load on that branch circuit.

Best accuracy can be obtained by becoming familiar with the operation of the load on line test. The distance of the SureTest from the load will affect accuracy. Try to position the SureTest close to the largest load on line.

For best accuracy, power up all loads and make certain they are working at their normal rate of operation, then plug the SureTest into an appropriate
nearby outlet on the same circuit. The Load on Line will be very close to
the actual load. The maximum current measured is held in the small display at the top right hand corner. This value will be held until the Sure Test is removed from the outlet.

While you may do so, the accuracy will suffer if loads are turned on and off during the test period. To quickly confirm a questionable reading, remove the SureTest and reinsert it to recalculate with all loads running.

Due to the proprietary method used to calculate the load, variations in the line and neutral resistance can cause significant variations to the accuracy of the displayed current. Ideally, there should be less than 5% Vd and less than 0.25 Ohms of resistance. In cirical applications, it is recommended that a traditional current clamp such as the Ideal Model 61-746 be used at the panel to obtain a very accurate current measurement.



ESTIMATED LOAD ON LINE.

The estimated load on line (ELL) is limited to a maximum reading of 15 amps, to best reflect actual conditions on the line as the data is monitored. The Peak Hold display will monitor the load as long as the SureTest is plugged into the outlet. It indicates an estimate of the maximum load on that circuit over time. The calculation is based on the
peak current flowing in the neutral conductor. Neutral current is the
result of powered equipment on the line. The ELL will also help indicate circuits that are overloaded, and those that have a common neutral. This is especially important when the circuit being measured powers single phase switching power supplies, like computers. The third harmonic generated by this equipment is not cancelled, and returns on the neutral, causing overload and heating of the neutral conductor. This is particularly true in 3 phase 4 wire panels, (120/208) where third harmonic is very common. The test allows determination of the remaining capacity of the circuit. It can also help determine whether or not the circuit is dedicated, since a circuit with no load will have very low or zero neutral to ground voltage. Any reading over 1 amp indicates the circuit is very likely not dedicated.

The load on line is strictly an estimate. This is an indirect reading, so there may be significant error in the reported values.

The SureTest does not have to be in the furthest outlet on the branch circuit. Accuracy will decrease significantly with distance. Worst accuracy will result when the load is between the SureTest and the distribution panel.

To get the very best results, the SureTest should be plugged into the same outlet as the load, with no other loads on line.

Remember that shared neutrals will indicate the current flowing from both hot wires. If the ground wire is carrying current, there will be significant error introduced, and this is a dangerous situation that should be rectified immediately.

Bill, thanks for a great run down on the ELL features. They sound very useful, especially on 3rd harmonic (non-linear load) effects and could help prevent overheated neutrals.

Have you been talking w/ Ideal or did you get this out of their manual?

 

[electricguy61]

i got one for a couple reasons.... i had a neutral fault test to pass,
and this made it easier to find the cross connect. as i posted earlier,
it'll detect a neutral / ground cross connect upstream for about 15'.

that'll let you test without loading the circuit. it's fast.

here's the other reason.... all the inspectors around here are starting to
get them. i don't call for inspection unless i know it'll pass, and if i don't
have the tool the inspector is gonna use, well, it's a crap shoot.

now, here's what i learned on here... dunno if it is out yet, but the newest
generation of suretest will tell the amount of load on a branch circuit, from
any point in the circuit.

so, if you are gonna buy one, check and see if the unit you buy has that
feature yet... mine doesn't......

it's also an excellent diagnostic tool on a number of levels. i had a 'pooter
network administrator having his undies in a wad about a power source
for his server.... i stuck the suretest on the outlet, and it comes up with
info that looks like this... it settles a lot of discussions.

first screen: all wiring correct, no cross connected neutrals / grounds

second screen: 121.2 volts rms h/n
0.1 volts rms n/g
171.3 volts h/n peak
60.0 hz frequency

third screen: voltage drop 4.4% @ 15 amps, 115.5 volts available
voltage drop 5.8% @ 20 amps, 113.9 volts available
voltage drop 3.5% @ 12 amps, 116.7 volts available

fourth screen: 480 amps bolted fault available at that point, h/n
550 amps bolted fault available at that point, h/n/g

fifth screen: .34 ohms total impedance, hot
.02 ohms total impedance, neutral
.25 ohms total impedance, ground

all of the values are from the point of connecton to the secondary winding
of the poco, or next upstream transformer.

sixth screen: gfci trips at 164 ms @ 7.4 ma

seventh screen: afci test... here is the instructions from the manual:

"AFCI breakers are prone to nuisance tripping when wired with a shared
neutral or when the neutral conductor is accidentally grounded before
the panel. The AFCI tripping occurs because it senses an imbalance
between the current going out on the hot and the current returning
on the neutral. A shared neutral between two hot conductors creates
this imbalance.

The SureTest can test for these conditions by applying a small load of 300mA
between hot and neutral to simulate a normal load and ensure that the AFCI
breaker does not trip. To conduct a shared neutral test, press the AFCI
button to enter the AFCI main menu. Press the side arrow ( ) to highlight the
NEUT symbol. Then, press the AFCI button to activate the test. The TEST
icon will light brightly while the test is being conducted. The AFCI breaker
should not trip. If the breaker does trip, a shared neutral is the probable
cause.

What model did you buy? Please be as specific as possible. Thanks

 

[wptski]

Bill, thanks for a great run down on the ELL features. They sound very useful, especially on 3rd harmonic (non-linear load) effects and could help prevent overheated neutrals.

Have you been talking w/ Ideal or did you get this out of their manual?

Long time ago I had some questions about their 61-830 VPM that nobody could seem to answer. I guess my questions were passed along as I got email from this guy at Ideal. He must have designed the VPM!

I kept his address and have emailed him with other questions. Last July during a Q/A session, he gave me that info.

I haven't checked lately but a few months ago the online version of the 61-165 still didn't include ELL yet.

I called Friday to get my RGA# and have my 61-165 ready to go tomorrow.

I remember being told that they were working on the issue that the Suretest trips a GFCI on the ground impedance test. I wonder if they fixed that problem?

 

[ohm]

i got one for a couple reasons.... i had a neutral fault test to pass,
and this made it easier to find the cross connect. as i posted earlier,
it'll detect a neutral / ground cross connect upstream for about 15'.

that'll let you test without loading the circuit. it's fast.

here's the other reason.... all the inspectors around here are starting to
get them. i don't call for inspection unless i know it'll pass, and if i don't
have the tool the inspector is gonna use, well, it's a crap shoot.

now, here's what i learned on here... dunno if it is out yet, but the newest
generation of suretest will tell the amount of load on a branch circuit, from
any point in the circuit.

so, if you are gonna buy one, check and see if the unit you buy has that
feature yet... mine doesn't......

it's also an excellent diagnostic tool on a number of levels. i had a 'pooter
network administrator having his undies in a wad about a power source
for his server.... i stuck the suretest on the outlet, and it comes up with
info that looks like this... it settles a lot of discussions.

first screen: all wiring correct, no cross connected neutrals / grounds

second screen: 121.2 volts rms h/n
0.1 volts rms n/g
171.3 volts h/n peak
60.0 hz frequency

third screen: voltage drop 4.4% @ 15 amps, 115.5 volts available
voltage drop 5.8% @ 20 amps, 113.9 volts available
voltage drop 3.5% @ 12 amps, 116.7 volts available

fourth screen: 480 amps bolted fault available at that point, h/n
550 amps bolted fault available at that point, h/n/g

fifth screen: .34 ohms total impedance, hot
.02 ohms total impedance, neutral
.25 ohms total impedance, ground

all of the values are from the point of connecton to the secondary winding
of the poco, or next upstream transformer.

sixth screen: gfci trips at 164 ms @ 7.4 ma

seventh screen: afci test... here is the instructions from the manual:

"AFCI breakers are prone to nuisance tripping when wired with a shared
neutral or when the neutral conductor is accidentally grounded before
the panel. The AFCI tripping occurs because it senses an imbalance
between the current going out on the hot and the current returning
on the neutral. A shared neutral between two hot conductors creates
this imbalance.

The SureTest can test for these conditions by applying a small load of 300mA
between hot and neutral to simulate a normal load and ensure that the AFCI
breaker does not trip. To conduct a shared neutral test, press the AFCI
button to enter the AFCI main menu. Press the side arrow ( ) to highlight the
NEUT symbol. Then, press the AFCI button to activate the test. The TEST
icon will light brightly while the test is being conducted. The AFCI breaker
should not trip. If the breaker does trip, a shared neutral is the probable
cause.

I reviewed your post and saw a couple of interesting items:

1) At 20A you have 5.8% VD ..a bit too much

2) 480 A of bolted fault energy is available from h-n and 550 A from h/n/g which is well above the 75 A minimum for AFCI testing.

 

[ohm]

Long time ago I had some questions about their 61-830 VPM that nobody could seem to answer. I guess my questions were passed along as I got email from this guy at Ideal. He must have designed the VPM!

I kept his address and have emailed him with other questions. Last July during a Q/A session, he gave me that info.

I haven't checked lately but a few months ago the online version of the 61-165 still didn't include ELL yet.

I called Friday to get my RGA# and have my 61-165 ready to go tomorrow.

I remember being told that they were working on the issue that the Suretest trips a GFCI on the ground impedance test. I wonder if they fixed that problem?

Great to have a man on the inside!

 

[wptski]

Great to have a man on the inside!

I looked at Ideal's site and manual still doesn't include the ELL feature.

 

[Fulthrotl]

What model did you buy? Please be as specific as possible. Thanks

61-165

about $300

 

[Fulthrotl]

I reviewed your post and saw a couple of interesting items:

1) At 20A you have 5.8% VD ..a bit too much

2) 480 A of bolted fault energy is available from h-n and 550 A from h/n/g which is well above the 75 A minimum for AFCI testing.

code limit is 5% for feeder and branch circuits.

that 5.8% number includes the breaker and the service entrance conductor,
and the clips for the meter socket. and the panel is a circa 1964 zinsco
"prince of darkness" residential special, with aluminum bus bars in a
salt air environment.

that is total impedance all the way to the xfmr secondary on the pole.

what's interesting is looking at the impedances on the different conductors.
if you've got a bad breaker or breaker/busbar connection, that impedance
on the neutral may be .25 ohms, and the impedance on the hot conductor
may be 2.5 ohms.... and 2.5 ohms at 120 volts and 20 amps is...

P=I2*R = 1000 watts. that breakers gonna get nice and toasty.

so, checking a circuit on the same panel that isn't crunchy will give you
a baseline, and then you look at the difference, and you know where you
need to start looking....

as for the bolted fault current, i'm taking that one with a grain of salt.
it's an inference drawn from impedance of the circuit, and i think that it
might be a generalization. the same with the branch circuit current flow...
it's a rough number, and if ya need to know exactly, it's time to pull
a panel cover and get out the amprobe.

 

[ohm]

code limit is 5% for feeder and branch circuits.

that 5.8% number includes the breaker and the service entrance conductor,
and the clips for the meter socket. and the panel is a circa 1964 zinsco
"prince of darkness" residential special, with aluminum bus bars in a
salt air environment.

that is total impedance all the way to the xfmr secondary on the pole.

what's interesting is looking at the impedances on the different conductors.
if you've got a bad breaker or breaker/busbar connection, that impedance
on the neutral may be .25 ohms, and the impedance on the hot conductor
may be 2.5 ohms.... and 2.5 ohms at 120 volts and 20 amps is...

P=I2*R = 1000 watts. that breakers gonna get nice and toasty.

so, checking a circuit on the same panel that isn't crunchy will give you
a baseline, and then you look at the difference, and you know where you
need to start looking....

as for the bolted fault current, i'm taking that one with a grain of salt.
it's an inference drawn from impedance of the circuit, and i think that it
might be a generalization. the same with the branch circuit current flow...
it's a rough number, and if ya need to know exactly, it's time to pull
a panel cover and get out the amprobe.

Actually P=2000 using 20^2 * 2.5 so toasty is really hot! And it will go up as the connection gets hotter.

Also, one would expect the ground to be the lowest Z since it has no I^2 * R losses and should be cool & it's in parallel with the building ground and the pole ground.

I forgot to ask...was that circuit w/ 5.8% VD a 20A or a 15A? Even if the wire back to the pole is included it should be very small (4/0 AL?).

A similar test on the opposite phase would clear up a lot.