How To Detect Electrical Wiring Errors With A Clamp-On Ammeter

There is one aspect of EMFs that is commonly overlooked.

Electrical wiring errors. New homes, old homes, wiring errors are common in many homes.

So what’s the big deal with these wiring problems?

Why Are EMFs From Electrical Wiring Dangerous?

The big deal is that electrical wiring errors can be a significant source of electromagnetic fields or more precisely ‘power frequency electromagnetic fields’.

Power frequency EMFs have been linked to:

  • leukemia (especially in children)
  • brain cancer
  • breast cancer
  • increased risk of miscarriage
  • Alzheimer's disease
  • reproductive problems and birth defects
  • depression,
  • blood disorders,
  • heart disease,
  • sleeping complaints
  • and a host of other ailments.

Wouldn't I Know If I Had Wiring Errors?

A lot of people think that because their electrics appear to be working correctly that they don't have a wiring error. WRONG. Everything may appear to be working correctly but your electrical installation could still be emitting very high levels of magnetic fields. The only way to know is by doing some simple tests with an inexpensive meter.

A few weeks ago I interviewed Electrical Engineer and Building Biology Environmental Consultant Spark Burmaster on the topic of electrical wiring errors.

Why Do You Need A Clamp-On Ammeter?

One of the things I came away with from the interview was the importance of having a clamp-on ammeter for detecting electrical wiring errors. Here's how Spark explained it:
Basically, in terms of fixing wiring errors, the Gauss meter is what tells you there’s something going on. But the problem with the Gauss meter with wiring errors is that if one single error can make magnetic fields all over the house.

So you could just have one single wiring error and you can have elevated magnetic fields in three rooms. Therefore, it’s extremely difficult to trace down a wiring error with a Gauss meter.

So the purpose of the Gauss meter is to tell you there’s something wrong. But then you need a clamp-­on ammeter to measure current to find what the actual problem is. And then once you fix the problem electrically, use the Gauss meter again to verify that you’ve fixed the problem.

Practical Uses Of Clamp-On Ammeter?

Detect Wiring Errors With A Clamp-On Ammeter

So I decided to invest in a clamp-on ammeter. I bought this: Uni-T UT210E True RMS AC/DC Current Mini Clamp Meter.

I experimented with it and then contacted Spark for his advice on the practical uses of it.

For that kind of money (ridiculously cheap), specs (1 ma, AC&DC etc.) reviews (85 % 5 star, 13 % 4 star) I ordered one to try out.

The good news is that the unit is small making it easy to carry around. The bad news is that the clamp unit is also small making it difficult to clamp water pipes.

Yes it is true that one has to have the clamp closed to get an accurate current flow reading. With respect to usage, if one is just a “person” the clamp-on ammeter is used to demonstrate there is a wiring problem.

If one is a technical person actually solving a wiring problem, then a current flow clamp-on ammeter is a critical/required component of the equipment used to find and repair wiring problems.

The current flow clamp-on ammeter is used to tell:

  1. if you have current flow where it is not supposed to be, such as a grounding conductor [green wire in the US] or water pipe.
  2. if one clamps an electrical cable (hot, neutral ground) and it reads non zero, (with or without a load on) there is a problem.
Further analysis / testing required to solve any problems. If you are a screwdriver/electrical person and you are doing actual wiring trouble shooting and repair, then a clamp-on ammeter is a required weapon of choice. Basically it is impossible to trace and fix wiring errors without a clamp on to tell you what is happening.

The 1 milliamp (mA) resolution on this model is a good low end desired specification. All this is mindful of the fact that whoever has their hand on the screwdriver has taken on the responsibility of any results including any damage and getting all intended loads to work at the end. If you are not a screwdriver/electrical person you can use the clamp-on meter to find the existence of errant current flow and thus can show the electrician etc. that there is errant current flow that the electrician needs to get rid of.

Thus you will prove there is a problem, but not what the actual physical problem is and what to do about it, other than leaving offending circuits turned off.

In the USA many times cabling is visible on unfinished basement ceilings. Also many times electrical panels are surface mounted so the cables leading into the panels are accessible for clamping.

Testing For Wiring Errors In An Electrical Panel

Detect Wiring Errors With A Clamp-On Ammeter in an electrical panel
Image created by Spark Burmaster, copyright, used here with permission

Here is a grossly simplified procedure summary to use the clamp-on to trace current flow.

  • go to the Electric Panel,
  • shut it off [on the main breaker] and use the screw driver to open
  • with the whole panel off, cover with insulation material any exposed hot components.
  • then test each branch circuit neutral individually.
In the end, ideally in the end one can clamp any metal (except individual hots and neutrals that have a load on) and one should read zero current flow.
I use a device that generates a low voltage safe 60 Hz signal to run through each branch circuit neutral individually and the clamp on to trace out the injected signal and thus find and fix any wiring errors.
Some people trace current in still on hot circuits. I avoid this as dangerous for a variety of reasons (getting shocked etc.).
It doesn't matter what loads are present as we have all the hots off. See attached diagram of the device in use.'

Detect Wiring Errors With A Clamp-On Ammeter

Clearly having a clamp-on ammeter is very useful in detecting wiring errors. This is NOT about conducting electrical work. It's about being able to detect wiring errors with precision and in an ‘electrician friendly way'. Because if you telephone your electrician and say to him ‘I've got magnetic fields', it's very possible he won't know what your talking about. But if you say I measured my water pipe with my clamp-on and it's got current on it or I measured my grounding conductor and it's got current on it, then he'll understand.

Which Clamp-On Ammeter Should You Buy?

I live in France, electrical current on water pipes is not really an issue (my water pipe is plastic). The Uni-T UT210E is a good choice because I don't need to clamp around my water pipe. But in many parts of the world (notably the US) electrical current on water pipes is a very common problem.

In which case a clamp-on ammeter with a bigger jaw would be more suitable. You can get clamp-on ammeters with jaws over 50 mm wide (compared to 17 mm with the UT210E) but they tend to be pricey. A good compromise is the Fluke 323 True-RMS Clamp Meter Fluke 323CAL which has a 33 mm jaw. Fluke make some excellent meters and this one has particularly good reviews on Amazon.

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  • Rosemarie Russell said,

    Thank you! I have put the meter in my basket to purchase.
    I am an avid DIY Diva so your detailed instructions are greatly appreciated.

  • Charla said,

    Super article Lloyd. I had looked at clip-on ammeters and was dismayed at the prices. This one fits the bill. Thanks for the review and instructions.

  • Lynn said,

    Would like to start on easier things first and I need clear instructions like some of the YT vids. Currently have a volt meter , a ground outlet tester, and non-contact voltage detector. Did find this and this page . Trying to find easy instructions to test if current at sink. Would we use a volt meter on the faucet or the water? Thanks

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