[geeks] Questionable Voltage

Sridhar Ayengar ploopster at gmail.com
Wed Dec 5 16:25:20 CST 2007


der Mouse wrote:
>>> [...]
>> I'm aware of all of the above.  I just am unable to measure without
>> unplugging something, which I can't do right now.
> 
> One thing you might be able to do is to unplug a plug just enough to
> get voltmeter probes in to touch the prongs.  Then compare that to a
> measurement made at the breaker box, or at an outlet on un unloaded
> circuit (but make sure it's on the same phase).

I managed to get something unplugged just now.  It appears as though I'm 
probably not losing enough voltage to cause my flakiness.  It starts at 
120.1V and lowers down to about 114.9.  That's still within the 
specified input range of my devices, I believe.  Plus, the audio 
amplifier isn't clipping.

>> The breaker panel is almost new.  The wiring is 80+ years old.
> 
> Urk.  Under those circumstances, I'd consider the wiring guilty until
> exonerated, myself.

I might upgrade the wiring just in case.  Better safe than sorry.  I'd 
rather not take chances with fire.

>>> Given the questions you're asking, I offer the thought that you
>>> might actually not be qualified to wire it up yourself.
>> Oh, I've rewired an entire house before and wired in generator backup
>> systems and rotary phase converters before.  It's just that wiring
>> this old is outside of my experience.  There's still knob-and-tube in
>> places, so it appears I have my work cut out for me.
> 
> Well, knob-and-tube is outside my direct experience too; I was speaking
> from general principles, not from having worked with 80-year-old wiring
> personally.

Cool.

> I am reassured, though; it seemed odd for _you_ to be asking those
> questions, and I'm glad to hear you're already aware of the things I
> felt needed bringing up.

Coming from you, I'll take that as high praise.  8-)

Peace...  Sridhar



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