Double death capacitors?

[Axtman]

Are both C3 and C4 the infamous death capacitors?

[The Dude]

The one circled in red isn't a death cap. It's across the line- not from line to ground. Probably EMI/noise filtering. That said, I don't really like the fact that it's ahead of the breaker. IMO, it should be after the breaker in case it shorts. The one circled in blue is a death cap.

[Leo_Gnardo]

Are both C3 and C4 the infamous death capacitors?

The one circled in blue (or is it black) yes, a death cap. The one circled in red is across the AC line, from hot to neutral. Sometimes these are placed to suppress "hash" noise on the AC line,either arriving at, or possibly leaving an AC powered device. "Hash" being motor noises, digital/RF trash, noise from SMPS hi frequency switching, ticks & clicks from switching large loads in or out. A cap here should also shunt any RF picked up on AC cables acting as antennae - help keep out interference from various radio sources like AM/FM broadcast, CB, TV transmitter, emergency/police/military/aircraft or the errant taxi or walkie-talkie. Anything but the nice pure sine wave that the AC line should be, in other words. Just a simple cap, doesn't always work all that well, but cheap and better than nothing.

[garytoosweet]

Red circle 'Across the Line' cap should be replaced with an 'X' rated safety cap.

https://www.allaboutcircuits.com/tec...-y-capacitors/

https://www.mouser.ca/ProductDetail/...rrencycode=CAD