The BC547B has Vcbo=50V, Vceo=45V, Vebo=6V, where-as the BC548 in original circuit has Vcbo=30V, Vceo=30V, Vebo=5V, rest of the parameters being pretty same as per datasheet (hFE:220-450). 1HP Water pump (220VAC, 800W) - One thought is to use higher current rated (e. g. 30A) relay. But, I think I need to worry about EM feedback which might cause arcing and destroy the EM relay.
Q3) Right now I am making this on a veroboard (el-cheapo phenolic kinds). While I understand that this may be sufficient for the lamp/fan control, I am wondering if I need something better for higher loads, s. a. the Water-pump control What is the minimum gauge wire to be used for this purpose What kind of connectors (terminal blocks) could be used