Current topicsSafety Warning Concerning Ensto Load Break Switches
Ensto Control Oy has recently received reclamations on a small number of cases, where a load break switch has malfunctioned under normal use. The malfunction may cause one of the electrical poles to remain connected, even if the switch is turned to the position 0 (OFF).
Note! This malfunction may cause a danger to life during electrical installation and maintenance work.
The cause and the scale of the defect
The malfunction in a small number of cases is caused by a plastic part that has broken inside the switch. In cases where the part is broken one of the poles (phases L1 or L3) may remain connected even if the switch is in the position 0 (OFF). Analysis of the root cause of the breakage is on-going.
Our first analysis indicates that the defect is possible in switches manufactured in 2007 in weeks 27-50. However, we cannot yet guarantee that the switches manufactured during the first half of 2007 in weeks 1-26 are without the defect.
Our estimation is that the defect concerns less than 2 % of the switches manufactured before the week 51 in 2007. The manufacturing week and year is stamped on the bottom of the switch (e.g. 5107).
The risk of the defect concerns the load break switch models mentioned in the table attached below.
The defect has been eliminated in switches manufactured in week 51/07 and thereafter.
Required actions
As an immediate precaution we instruct all our customers to check with care that electrical circuits are disconnected when the switch is turned to the position 0 (OFF) before making any electrical installation and maintenance work. In addition, we request our customers to make sure that all their customers and end users have received this warning.
As corrective action we instruct our customers:
• To return from their stocks to Ensto all concerned switches manufactured during the period 1st Jan – 14th Dec 2007.
• To take actions in order to replace all the concerned switches which may have been delivered as components or as part of their products. When replacing the concerned switches we instruct to prioritise first the switches manufactured during the weeks 27-50.
Ensto will cover the costs of the replaced switches and the replacement work.
An Ensto representative will contact your company as soon as possible to agree on the necessary actions.
Further information
Product Manager Jan Andersson (tel. +358 204 76 21, e-mail: firstname.lastname(at)ensto.com).