Mention voltage drop?

Is voltage drop something you mention if you notice high readings? My suretest detected 33% on exterior and bedroom outlets. I know a drop of about 7 or so % is recommended, but not required. Any thoughts? Thank you

What was the voltage down to under load, and at start, and at the panel.

Voltage drop is often due to high resistance in the circuit. High resistance generates heat and greater resistance.

I think your client deserves to know this.

Often back stabbed outlets have bad connections and overheat the plug and lower voltage down line on the circuit.

Sorry David, not sure what your asking me. I test by visually examining the panel and visible conductors, and by plugging in the suretest and reading. It tells me 7-10% on what I believe is the first outlet in the run and 30-33% at the end of the run on ext. and int. outlets. Not much else I can say. Sorry

The way I see it, is I am getting over my head a little bit when I start pointing things like that out. I do have a narrative that you could look at. I have not submitted it yet, so any comments or “constructive” criticism are appreciated.

Higher than recommended voltage drop was observed. Current standards recommend, but do not require, a voltage drop of no more than 5%. Drops in the range of 30-35% were observed on exterior outlets and bedroom outlets. This condition can cause overheating in the conductors. This leads the inspector to believe that less than professional standards were utilized for installation of the branch circuits. You should consult a qualfied electrical contractor for more information, as this does exceed the scope of a typical home inspection.

A voltage drop of 33% means either there is a serious problem with the circuit, or a serious problem with your tester.

How does the SureTest measure VD?

I don’t know how, but it does. Just like those dupont commericials, I just plug it in and it works. I have a pic. This house is a remod with many defects in the new hvac, plumbing, and electrical. The client is an electric engineer so I took a closer look for him.


“This leads the inspector to believe that less than professional standards were utilized for installation of the branch circuits.”

I would leave that line out. There are varying factors that could lead to a high voltage drop. That does not mean that less than professional standards were utilized. Why beat up the electricain before you know the cause. Just write what you see and defer it out.

Good point William. That line is in there because of the rest of the house. The same company appears to have done all the work- hvac, plumbing, elec, and roof. Each component was “less than professional”. Would you replace the line with something or just omit it?

Well, considering your explanation, and the assumption that other receptacles in the house don’t have this much drop, I think we can rule out faulty tester. :mrgreen:

My opinion is the “leads inspector to believe that less professional standards were utilized” is speculating and really irrelevant anyway. You have already done your job and identified the problem. Just defer and let the “Pro” figure out the source and remedy. :slight_smile:

I find the newer suretest to be inaccurate when testing volt drops and, well pretty much everything…

If I plug in my suretest I get a reading of no ground, rev. polarity, high volt drop etc. but if I pull it out of the receptacle and plug it back in these “defects” are gone.

False readings
Sent unit in once already
Replaced cord twice

and I’ve had it for under two years…:roll:

I agree.

I ran across this, tonight.


Good find, James.

I also agree that this does not have any place in any home inspection report. It is not factual and you have nothing to support this other than opinion.
Someone can build a house not the standard as we would expect and it will last as long as any other. This really has no bearing on the inspection. If the nonstandard practice results in a deficiency, write it up.

Just because an electrician backstabs the plug outlet, does not mean it’s substandard work; even though in most cases where voltage drop exist, it is a result of this practice. It doesn’t make it nonstandard (because it is practiced the majority of the time). That’s what the sure test is for, to locate these deficiencies.

I highly recommend that before you start reporting anything in your inspection report based on an electronic measuring device, that you understand what the device does and what substandard readings indicate.

I have the same beef with home inspectors that try to report the age of a piece of HVAC equipment as being “close to the end of its expected life” when they have no supporting evidence, nor are they required to evaluate or predict this life expectancy. Just because there’s very little that anyone can do to inspect HVAC does not mean you have to make stuff up to impress your client or cover your butt. Your client can see that the appliances are old, I don’t see any reason to try to cover your butt because it may break in the future.

Someone posted a picture of a “about to expire” furnace this week, and it looked 10 times better than the two HVAC units on my house (which are a functioning better than any in my neighborhood). Yes, they will need to be replaced in the future (most likely because the cabinets will rust out and not support the condenser fan). Both of my units have thermostats to prevent the auxiliary heat from coming on unless it’s actually cold outside (so people playing with the thermostat don’t turn it on when they crank up the heat), it has multiple defrost sensor systems to ensure there is 1/8 of an inch of frost on the condenser coil before going into a defrost cycle (not just real cold outside), it has a time delay on the indoor fan to allow a coil to warm up in the heat mode before blowing cold air in the house, it also has a purge cycle to get the heat out of the air duct, the heat banks are staged based on return air temperature so they don’t overheat and waste money, both have new compressors, both have new accumulators, both have new compressor contactor’s, both have new indoor fans which are now variable speed controlled so they don’t blow so much air in the wintertime and make you feel cold .

So, when you come to my house and look at the unit and say it needs to be replaced based on age (though you can’t read their nameplates anymore) and the outside Cabinet has rust on it, you are condemning a piece of equipment that operates more efficiently and cost effective than anything new that you can buy.

Is the inspector going to report that the unit has been worked on under less than normal standards? Only if they can figure it out! If I move, the units will most likely be replaced because the HVAC technician can’t find a wiring schematic.

Your inspection report should educate your client and report on significant deficiencies. You spent good money on a device, learn to use it properly and document accordingly.

[size=2]In the case of my house, it would be prudent to admit that you don’t have a clue about what’s going on because some anal HVAC engineer must have previously owned this equipment! But its running fine, looks like crap and will eventually need replacing (as they all do).

Good article Jim !

Dylan, this article is discussing the other readings I was talking about and their relationship to what is a significant problem.

You should always follow up electronic measurements with other investigative techniques or equipment when possible. As Speedy Pete mentioned, comparison of baseline test (outlets next to the service panel versus outlets at the furthest distance from the panel) gives a differential that is probably more meaningful than the actual numbers displayed.

I look at the percentage of voltage drop, and when I find it high I look at all of the other information the testing device gives. Beginning and ending voltage, resistance on the conductor, which conductor has the high resistance etc.

This is one way I follow up.

Thank you David,

And short of using an $8,000-$10,000 camera for follow up, which other methods would you utilize? I do know how to use the suretest. As mentioned above, I test what I believe is the start, middle, and end of the circuit. I just usually do not report the situation, which is why I started the thread. I only brought it up to my client because he is an electrical engineer and seemed very concerned about it before and after the inspection.

And I do appreciate the feedback on the narrative from everyone. It will be edited before submittal. I don’t know what I would do without the advice, besides get myself in trouble.

Just be sure you are reporting something factual.

I have received several irate phone calls from electricians.
They don’t have a clue what, or how to test voltage drop.
With the price of copper out of sight, I find more skimping on the long runs.

I pull cover plates and see if they are back stabbed.
Yes, it is their SOP to do it, but what do they do when the run is too long on small wire?

I have seen Electrical companies fired for unsubstantiated response to my inspection report. Builders have called to apologise.

I have had home runs made from other sub-panels to get the needed power to an important part of the house.

Now this stuff is in very large homes with business applications.

I always ask my clients how they plan to use the house.

I always test outlets next to cable outlets. They are likely to have electronic devices that can’t stand low power supply.

When you have 120 at an outlet near the panel and 90 VAC in the master bath, I think this is a concern.

I have spent a lot of phone time with Paul Abernathy (where is he, by the way?) and you can just do the math and show it can’t work!

Cheaper IR thermometers work well, you don’t need the picture.

When you report, put all the information the sure test provides in the report. Just >5% is not sufficient. But 87 VAC under a 15 amp load needs consideration.

Lot of good considerations to keep in mind there. Nice.

I would omit it and just state what I see and defer to be corrected. I have on occassion used the word “installed in an un-workmanlike manner” in a situation such as yours, but that is usually when I can back it up with pictures.