Any Idea what this is doing int he panel box?

[Matt Shapiro]

Any clues as to what this is or why it is installed in the circuit breaker at the panel box? Regardless, I have already called it out. The home was built in 1986.

Thanks in advance.

[Steven Saville]

Capacitor placed across phases to allow X-10 home automation signals to be sent and received on both phases of the service. Commonly referred to as "phase coupling. I've done this years ago when I used X-10 controls extensively.

Here's some additional information...

X-10 Phase Coupling (http://kbase.x10.com/wiki/Phase_Coupling)

[Matt Shapiro]

Thanks. In a million years I would have never known what was it use.

[Bruce King]

Any clues as to what this is or why it is installed in the circuit breaker at the panel box? Regardless, I have already called it out. The home was built in 1986.

Thanks in advance.


You were correct to call that out, its an unsafe shortcut that is explained in the link that Steven posted:

One technique we have heard about but do NOT recommend is to put a 0.1uF, 600VDC capacitor across the phases. A capacitive load is exactly the opposite of an inductive load (the lower the frequency the more it attenuates the signal). With the right capacitor it won’t let the 60Hz power through but the 121kHz X10 signal will be coupled to the other phase with very little attenuation. X10 does not recommend coupling phases with just a capacitor. There are many disadvantages to this 'solution':
It is not approved in the electrical code. X10 expressly disclaims all liability for any electrical damage, house fires, or any other mishaps resulting from this DANGEROUS procedure that we do NOT recommend.
Electrical noise will be coupled between phases along with the X10 signal
220V modules won’t work (Space does not permit an explanation of why this will not work)
Note the "right" capacitor is hard to find because it depends on the resistance of the copper lines carrying the phases (thus forming a high pass RC filter) - and this can vary quite a bit from house to house. In the worst case a "wrong" capacitor can effectively short the two phases together.

[Matt Shapiro]

Interesting. As usual, even though they say it should not be installed at the breaker, it is. Keeps us in business.
I didn't know what it was but I knew it shouldn't have been there.

[bob smit]

That autta taught that lady bug not to mess wit electtracy.... burn the spots off yer wings:eek:
Reminds me off the 'one timers' and such, where the DIY or the 'I can do electrical' guy connects the cu stranded wires of the surge protector under a breaker with solid ones or even worse, aluminum.
I know I will always get a call on that rejection with the question as to "how do I connect this surge then, if I want to protect my (whatever)"?