Indications are confirmed guilty-innocent electronic development work needed!

Detector 1: After 8 weeks remained always hang the switching relay (as already reported by other shoppers). A short burst and it worked again ... for a while.
Detector 2: Same error after 3 weeks.
Our load: 3 pcs. Power supplies for LED strip a 40 Watt. = 120W total load. (How to switch the product 1200W is a mystery to me!)

Cause: Cheap relays caption for 10A / 250VAC is indeed designed lt.. But the (cheap) contacts remain by sparking when opening "stick".
Both replaced by OMRON sensors relay PCB Relay RS Components Cat. No. 6839141 PCB relay 10A 24Vdc 1 changer. Now works quietly and smoothly (about 2 weeks). If no entry follow - problem is resolved. :-)
The globalization components which are designed for 125V (USA), should not be sold on the European market.

January 2014: Error (contacts remain sticking) also joined here again.

02/04/2014
Also an external power relay 16A (!) 24Vdc 1 changer got stuck after several weeks. Research revealed that switching power supplies; pull (a few milliseconds) and destroy all contacts (eg for LED between phase and neutral depends empty capacitor !!!) multiples (25-60A) to inrush current. We have 3 power supplies a 40W in use.
Only possibility is the initial current limit direction switching power supply.
RS Components Order number: 467 620, current limiter NTC 2,1W 10R; (NTC = negative temperature coefficient; start = cold = high impedance; limited power, is warm and then a low (er)!

Search time: total eight hours a xx Euro! Greeting the manufacturer :-)
Product manufacturers should refer to the intended use more.
So, the motion can not help it there! Therefore incremented back to 4 stars.