I should have specified I am hijacking your thread slightly to bring up some concerns of mine and hopefully get some more input to my design issues .(and maybe illustrate some potential hazards for US users).
Given you are in amsterdam how is your 240AC supplied as 3 conductors + ground or as 2 conductors +ground?
I am in the US where 220-240 is wired as 2 hot leads @ 110v and a common, +ground while your relay in your case is switching a pump just fine, my concern is when attempting to switch from other than the hot leads you leave a very hazardous circuit in place(especially for pumping conductive liquids).
So the real query here is and yes I am replying to the right post, is how exactly is the 240VAC oresented at the socket to you.
as a single 240AC conductor or 2 conductors? if as a single 240AC conductor then yes you will be ok with switching one hot lead.
And are you switching the the hot conductor(s) or ground lead with the SSR?
BUT if it is presented as 2 hot leads you may want to put a call into Crydom for a support inquiry like I did to the ballast manufacturer and to Opto22.
and on another side note, SSR(s) are being incorporated into HPS electronic(digital) ballasts already(too expensive ). Even Magnetic(transformer) ballasts can be accommodated with proper circuit design according to the data sheeet from Opto22.
and I was advised by ALL concerned to always switch the hot side NOT the ground, to do otherwise leaves a fully energized circuit just waiting for someone to make the connection to ground(with a part of their body).
Switching the hotside conductor(s) leaves only leakage current to deal with in the circuit, in addition I am also installing a 240ACGFI breaker.
Why all the caution? the design is ultimately meant for green house enthusiasts to add supplemental HPS lighting in fall and winter as well as part of a complete Hydroponic control system I am designing and implementing.
As I am older and suffering from CRS(cant remember S**T!), I am trying to design my circuit NOT to cause me an early end
(or any person who might attempt to duplicate my design(I am preparing a wiki pages on same eventually).
And finally the SSR will switch quite happily either the ground circuit or the hot side the safety depends on which path is switched.
Very happy your SSR is working for you though,I just wish the US system didnt make things quite so complicated(the SSR manufacturer loves selling 2X as many relays for these kind of apps I suspect.)
any comment on all my drivel above??
gwen(who is greatly upset by having his SSR budget doubled because of the above)
hmm you arent the same thomas S from rcgoups.com are you?