Re: Measuring impedance of wall socket

On Fri, 29 Jul 2005 00:46:43 -0700, "cyrille perron"
<cyrille.perron@xxxxxxxxxxxx> wrote:

>Hi, I'm not sure this is the best forum to post this question in but I was
>wondering how one would go about measuring the impedance of a wall socket?
>(Strange question, I know) I have some general ideas but would like to
>confirm my thinking. Any websites or other resources explaining the
>general concept would be greatly appreciated. Much thanks in advance.

Not a strange question at all, the only thing I find strange about
line impedance testing is how few testers are on the market and how
few electrical inspectors use them, considering how well they uncover
the most common and dangerous wiring faults (high impedance
connections, a common cause of fires) which are not otherwise easy to
detect. A google search on line impedance tester will however turn up
a few commercial testers.

If I were to build one I would use a bank of motor run capacitors for
a load, sized for about 10 A at 120 V for measuring typical US 15 Amp
wall socket impedance. By applying the load to Line-Neutral and then
Line-Ground voltage drop can be measured separately for all 3
conductors. Since the change in neutral to ground voltage provides
the voltage drop on the neutral or ground (whichever is carrying
current), the rest of the total voltage drop is due to the Line (Hot)
conductor impedance. Any other means of applying a load and measuring
voltage drop at a known current can acomplish the same thing.
.

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