TRIAC Circuit triggered due to interference
You are using a interesting configuration for TRIAC, but it is potentially unsafe for the component (TRIAC). My suggestion is to change the TRIACRES configuration as the bellow example.



Important: depending of TRIAC model, you need to use a SNUBBER circuitry to reduce the "false" positive on TRIAC GATE.

I learning a lot about TRIACs on the last 2 (two) months and I can honestly say to you: many of the samples in the internet are empirical experiments. It's important to calculate all the things in your circuitry before use any of this examples.

The picture above is from a Datasheet from Texas Instrument about MOC3020.

In most of the cases, you need to use the TRIAC MAX PEAK CURRENT in Gate port, because when you trigger in 90º Angle in a 110V Nominal AC, you have an equation like:

V = 110 * sqrt(2) = 154
I = ?
R = 180 Ohms


I = V / R = 0.85A --> it is a lot more than most of TRIAC Gates (about 50mA), but not exceeded the PEAK (around 2 or 4A for 20uS). To trigger you need only 10uS with 0.85A in 90º Angle at 110v Nominal -- in other words, 180R it's perfectly reasonable.

The Wattage of this resistors are important too. Including the package of you use (i.e. 0805, 1206 or PTH). If you use PTH --> 1/4W it's ok. But if you use a SMD you need to verify the Voltage of each Package. Probably for 110 Nominal, the most safe is 1206 -- 200VAC support.

If you have any doubt, please let me know. OK? And sorry about my english.