Ideal 61-165 Voltage Drop Tester

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ken44

Senior Member
Location
Austin, TX
Had an electrical engineer show up with one of these testers the other day to test a circuit in my rather old office building and said that the tester showed an 8.9% VD, the incoming voltage was 118 volts. From what I have seen in a few of these posts, the testers reliability seems to be in question. Can someone please point me in the direction of light so I can get out of the darkness.
 

mcclary's electrical

Senior Member
Location
VA
Had an electrical engineer show up with one of these testers the other day to test a circuit in my rather old office building and said that the tester showed an 8.9% VD, the incoming voltage was 118 volts. From what I have seen in a few of these posts, the testers reliability seems to be in question. Can someone please point me in the direction of light so I can get out of the darkness.

Check voltage at service panel. Check voltage at end of branch circuit under load. Do the math. Total VD from your feeders and branch circuit combined total should not exceed 5%
 

cadpoint

Senior Member
Location
Durham, NC
I can't comment on the tester itself!

Having read the manual, on line, that might be a little confusing as they implied, yes it could well be a problem, but if the circuit has multi-receptacles on the one circuit, then it's akin to crying wolf, and they are not very thorough, and not following the directions to find the Vd.

Was does everyone else one want to do our job! :roll:

Page 3 Ideal 61-165 (this is a retailers site - of the manual)
 

Smart $

Esteemed Member
Location
Ohio
VD measurement accuracy is stated as 2.5%+/-.2% as a percentage of the range, which is 0.1% - 99.9%. So an 8.9% reading could actually be as low as 6.2%.

When testing, was it verified there were no other loads on the circuit, as that will have a major impact on the measurement.
 

mivey

Senior Member
VD measurement accuracy is stated as 2.5%+/-.2% as a percentage of the range, which is 0.1% - 99.9%. So an 8.9% reading could actually be as low as 6.2%.

When testing, was it verified there were no other loads on the circuit, as that will have a major impact on the measurement.
I think it measures the dynamic response so it probably won't make a big difference for most of the loading we see.

You could always plug in a 1500 watt heater and measure the delta v & i to get essentially the same results.
 

wptski

Senior Member
Location
Warren, MI
I have one of those testers. Every single time I've used it voltage drop is very high. So now I don't use it.
Isn't that because if it was wired following NEC, it shouldn't have a high voltage drop? In some countries, they are requied to test and document voltage drops, here you don't.
 

kwired

Electron manager
Location
NE Nebraska
Amount of voltage drop is load dependent.

This device only will tell you what the results are for a few select amounts of current.

NEC does not have voltage drop requirements.

NEC does have FPN's that suggest a level of voltage drop.

Dealing with voltage drop is entirely a design issue - not saying it should be ignored.

For people that think you must have a maximum allowable voltage drop for all circuits consider the following:

If nominal system voltage is 120 volts, the actual no load voltage is 125 volts, and the equipment is marked 115 volts - Is your allowable drop based on 115, 120 or 125?

5% of 125 is 6.25 so if we drop that much the equipment is operating at 118.75 which is still above nameplate of 115.

Having a resistive vs inductive load will have an impact on the amount of voltage drop if you change the input voltage.

Is a motor designed to operate at 208 or 230 allowed to have more voltage drop when operating at 230 because the result will still be within the namplate voltage?


Voltage drop calculations typically only calculate the drop across the resistance of the conductor but do not include the effects of the change in load as a result of the voltage drop. Inductive loads will draw more current which will result in even more voltage drop. Resistive loads will draw less current because of voltage drop which will result in less voltage drop than if the current were to somehow remain constant.

Bottom line is really will equipment function properly and/or will it be effected over time by the reduction in voltage. Resistive loads will typically have a longer life at a reduced voltage. Inductive loads may have shortened life - a lot of other factors are likely involved in determing increased or decreased life on this. Non linear loads can have all kinds of issues with voltage or other power quality problems.
 

electricmanscott

Senior Member
Location
Boston, MA
Isn't that because if it was wired following NEC, it shouldn't have a high voltage drop? In some countries, they are requied to test and document voltage drops, here you don't.

Yeah, maybe I should get a code book then the tester will work better.

What are you talking about? :confused:
 

mivey

Senior Member
I have one of those testers. Every single time I've used it voltage drop is very high. So now I don't use it.
I've got one also. I use it as a test of the voltage drop, not as a substitute for voltage drop calculations. The instructions tell you to investigate further if the voltage drop is shown to be above 5%.

In other words, it is probably a good indicator that the voltage drop is within acceptable limits. It is not a definitive answer when it shows voltage drops that are slightly over the limit. It probably is a good indicator for voltage drops that are shown to be way over the limit.

I have not verified the accuracy of mine as it is just one tool I use to see if I need to look closer at a situation.
 

mivey

Senior Member
Amount of voltage drop is load dependent.

This device only will tell you what the results are for a few select amounts of current
But it is just another tool you can use to help identify possible problems. It is not the judge & jury but I think it is still a nifty tool.

Here are some hand calcs for various "test" loads and pre-existing loads (I don't know what the actual test load characteristics are in the Ideal meter).

Examples for a 100 ft run of #12:

10A & 20A test for pre-existing 5A load at various pf:

#1) 60%pf 5 amp = 0.92% (pre-existing load)
#2) 10A 100% pf = 2.93% (test with no pre-existing load)
#3) combined = 4.25% (test with pre-existing load)
#4) #3 less #1 = 3.33% (0.40% difference)

#1) 60%pf 5 amp = 0.92% (pre-existing load)
#2) 20A 100% pf = 5.87% (test with no pre-existing load)
#3) combined = 7.26% (test with pre-existing load)
#4) #3 less #1 = 6.35% (0.48% difference)

#1) 80%pf 5 amp = 1.20% (pre-existing load)
#2) 10A 100% pf = 2.93% (test with no pre-existing load)
#3) combined = 4.33% (test with pre-existing load)
#4) #3 less #1 = 3.13% (0.20% difference)

#1) 80%pf 5 amp = 1.20% (pre-existing load)
#2) 20A 100% pf = 5.87% (test with no pre-existing load)
#3) combined = 7.30% (test with pre-existing load)
#4) #3 less #1 = 6.10% (0.24% difference)

#1) 92%pf 5 amp = 1.37% (pre-existing load)
#2) 10A 100% pf = 2.93% (test with no pre-existing load)
#3) combined = 4.38% (test with pre-existing load)
#4) #3 less #1 = 3.01% (0.08% difference)

#1) 92%pf 5 amp = 1.37% (pre-existing load)
#2) 20A 100% pf = 5.87% (test with no pre-existing load)
#3) combined = 7.33% (test with pre-existing load)
#4) #3 less #1 = 5.96% (0.09% difference)


10A & 20A test for pre-existing 10A load at various pf:

#1) 60%pf 10 amp = 1.85% (pre-existing load)
#2) 10A 100% pf = 2.93% (test with no pre-existing load)
#3) combined = 5.34% (test with pre-existing load)
#4) #3 less #1 = 3.50% (0.56% difference)

#1) 60%pf 10 amp = 1.85% (pre-existing load)
#2) 20A 100% pf = 5.87% (test with no pre-existing load)
#3) combined = 8.50% (test with pre-existing load)
#4) #3 less #1 = 6.66% (0.79% difference)

#1) 80%pf 10 amp = 2.41% (pre-existing load)
#2) 10A 100% pf = 2.93% (test with no pre-existing load)
#3) combined = 5.63% (test with pre-existing load)
#4) #3 less #1 = 3.22% (0.29% difference)

#1) 80%pf 10 amp = 2.41% (pre-existing load)
#2) 20A 100% pf = 5.87% (test with no pre-existing load)
#3) combined = 8.67% (test with pre-existing load)
#4) #3 less #1 = 6.26% (0.39% difference)

#1) 92%pf 10 amp = 2.74% (pre-existing load)
#2) 10A 100% pf = 2.93% (test with no pre-existing load)
#3) combined = 5.79% (test with pre-existing load)
#4) #3 less #1 = 3.05% (0.12% difference)

#1) 92%pf 10 amp = 2.74% (pre-existing load)
#2) 20A 100% pf = 5.87% (test with no pre-existing load)
#3) combined = 8.76% (test with pre-existing load)
#4) #3 less #1 = 6.02% (0.16% difference)
 

wptski

Senior Member
Location
Warren, MI
Yeah, maybe I should get a code book then the tester will work better.

What are you talking about? :confused:
I did mention something that was incorrect! The testing required in some countries doesn't test for voltage drop but loop impedance which may cause a voltage drop. They used a loop tester like the Fluke 1653B which I've played with for about a month. You can't even buy one in the USA.
 

megloff11x

Senior Member
I have one and it failed to identify as "bad" receptacles which when stuff was plugged into them would not power up. They all passed the test and showed as low a Voltage drop as other known good outlets. It did trip the GFCI when that feature was actuated. I haven't had a chance to do an AFCI because I don't have one hooked up.

It does give me a warmer and fuzzier than boldly sticking DMM probes into an outlet or using a homemade "widow maker."

And it does tell when L & N are reversed or G not connected.

In other words it beats a sharp stick in the eye.
 

wptski

Senior Member
Location
Warren, MI
I have one and it failed to identify as "bad" receptacles which when stuff was plugged into them would not power up. They all passed the test and showed as low a Voltage drop as other known good outlets. It did trip the GFCI when that feature was actuated. I haven't had a chance to do an AFCI because I don't have one hooked up.

It does give me a warmer and fuzzier than boldly sticking DMM probes into an outlet or using a homemade "widow maker."

And it does tell when L & N are reversed or G not connected.

In other words it beats a sharp stick in the eye.
What was wrong with the receptacle that passed its test? Supposedly it won't detect a open neutral but would you get all LEDs as a good receptacal??
 

mivey

Senior Member
What was wrong with the receptacle that passed its test? Supposedly it won't detect a open neutral but would you get all LEDs as a good receptacal??
??? me too: the receptacle has to work for the Ideal tester to function.
 

mcclary's electrical

Senior Member
Location
VA
One thing this tester is extremely useful at, is detecting VD due to backstabbed receptacles. You can follow the line of receptacles, from beginning to end, and witness a percentage of voltage drop change with each added receptacle. By the time you get to the end of the chain of backstabbed receptacles, you'll see 12%-15% or so VD. Cut all backstabs,,,,land all wires on screws, retighten everything, and you'll see that number change drastically. I've witnessed it firsthand.
 
One thing this tester is extremely useful at, is detecting VD due to backstabbed receptacles. You can follow the line of receptacles, from beginning to end, and witness a percentage of voltage drop change with each added receptacle. By the time you get to the end of the chain of backstabbed receptacles, you'll see 12%-15% or so VD. Cut all backstabs,,,,land all wires on screws, retighten everything, and you'll see that number change drastically. I've witnessed it firsthand.

I think that's why we can't use backstabs for our connections in most places here in Northern CA (we can pigtail then backstab)

I bought the Ideal 65, hoping it would help in troubleshooting AFCI problems, but was sadly disappointed. I've found a very easy way to deal with those problems though.
 
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