voltage drop

[porsche6]

Im a fairly new inspector and had the opportunity to use a suretest analyzer. Upon testing several outlets, found many high voltage drops above 10%. This is a new condo. Can anyone take time to give me the ins and outs of this tester and if I even should be using this equipment when home inspecting
Thanks
Mike
Dynamic Home Inspection

 

[ron]

Re: voltage drop

Be sure you are using the correct setting for the type of circuit (15A or 20A).
There is no code requirement for a particular acceptable voltage drop. So after you establish the drop %, you can't do much with the information.

 

[bennie]

Re: voltage drop

Almost every lighting, and convienence outlet circuit in all houses, will fail when using the Sure Test Tester.
The loading, simulated by the testers, is not a true indicator of the circuit integrity.

 

[dereckbc]

Re: voltage drop

First, Ron is correct, there is no NEC requirement for voltage drop percentage.

Second, Bennie, IMO the Idea Suere test is accurate. I have compared it too a load box and found it to be reasonable accurate for field checks.

 

[iwire]

Re: voltage drop

Dereck I am sure Bennie can speak for himself,

[ April 02, 2004, 05:19 AM: Message edited by: iwire ]

 

[dereckbc]

Re: voltage drop

Originally posted by iwire:
[QB] Is the test a valid one for a dwelling unit?
What load does the suretest put on the circuit?/QB]

Bob point taken. It was late when I posted, and it came across to me that the meter is not accurate, I contest it is.

"Is it a valid test for a dwelling unit?" In the hands of a experienced user, it is a valuable tool to indicate the integrity of the circuit. One must know about how long the service, feeders, and branch circuits are, and if there is any other loads present. In a dwelling unit I wouldn't be too concerned about what the percentage of voltage drop is, but I would look a to make sure the ungrounded, grounded, and ground circuit conductors impedance are roughly the same (say less than .4 ohms, and approx equal to each other)

"What load does it put on a circuit"? A pulsed 15-amps between L-N,, L-G, and no load measurement from L-N, and L-G. From the measurements the meter can determine polarity, voltage drop, conductor impedance, proper/illegal N-G bonds, approx wattage of a device, etc.

As to the original question, should a home inspector be using one? Probable not. I have doubts a home inspector would have enough electrical knowledge, training, and experience to interpret the results.

 

[don_resqcapt19]

Re: voltage drop

It is my opinion that if you are using this type of tester you must first make a test at the panel to find the voltage drop on the utility supply system and subtract this voltage drop from that measured the receptacles.
don

 

[dereckbc]

Re: voltage drop

Don that is part of the experience, training, and knowledge equation. I agree you start at the main panel, check voltage, tightness of connections, etc, and make sure there is no load. No load is the key to getting accurate voltage drop readings, but typically 2% or less.

Having done that, the utility voltage drop is insignificant IMO. For example, a 200-amp service with a single receptacle having a 15-amp load test performed will have very little voltage drop developed on the utility side. Granted it is there, but insignificant and can be ignored IMO.

 

[porsche6]

Re: voltage drop

Thanks for all the responses, I greatly appreciate It.

 

[don_resqcapt19]

Re: voltage drop

Dereck,

For example, a 200-amp service with a single receptacle having a 15-amp load test performed will have very little voltage drop developed on the utility side. Granted it is there, but insignificant and can be ignored IMO

Only if everything on the power company side is ok. Many of these tests are being made by home inspectors on older buildings and the condition of the utility side is just as suspect as the building wiring.
Don

[ April 02, 2004, 08:59 PM: Message edited by: don_resqcapt19 ]

 

[websparky]

Re: voltage drop

Good point Don!

Not meant to be disrespectful to home inspectors;
Why is a voltage drop reading important in the first place? Secondly, why would a test made by an unqualified person hold any weight?

 

[bennie]

Re: voltage drop

The Sure Test Instrument applies a synthesized current on the entire loop. The voltage drop indication is factoring in the impedance of the transformer winding.

A load across the circuit, under test, will affect the reading of the instrument.

 

[bennie]

Re: voltage drop

I am certified by the State of Oregon as a home inspector.

I don't work at the business at all. The testing and experience exceeds that of a Supervising electrician license, and inspectors certification.

A home inspector has more clout than a municipality inspector. A home inspector can stop the money trail.

I compliment Mike for using the tester, and asking about the voltage drop feature.

 

[a.wayne3@verizon.net]

Re: voltage drop

Bennie here in Florida all one has to do to become a home inspector is attend a $250.00 class with no test afterwards,just attend and be certified.So to me home inspectors are well lets say not qualified to judge.Most are current on codes,and cite things that are not an NEC issue.Like last week ,cited no gfci within 6 ft of laundry sink we are 2002.So Bennie whats the article there.We have worked as electricians for years and here comes mister HI fresh from a class and tells H.O. things that are not an issue but they pay their $$$ and you dupe them.