Did You Know? Electrical Safety

Did you know or I should say are you aware that product design features need to transfer to manufacturing properly?

Discussion:  Most product designers can relate to issues on obtaining a compliant design when it comes to electrical safety.  Standards and approving agencies require that selected tests be accomplished on 100% of units produced prior to shipment.  These aspects are considered so critical to operator safety that all are tested.  Insulation is a part of the critical tests evaluated by a dielectric strength test.  The idea is that if the insulation is compromised, it will be revealed in the test.  During the qualification testing rigorous tests are accomplished but the factory test allows a little relief (shorted duration, no conditioning, etc.).  In the example below a manufacturing flaw was noticed during a random sample inspection.  Note that the insulation is damaged because a cable tie was tightened to a corner reducing the insulation thickness.  Results provide for arcing to metal parts of the unit.  Would this be detected during factory testing – hopefully but atmospheric influences could allow a pass condition and shipping vibration makes this unsuitable for use.  Root cause – inadequate manufacturing instructions on placement or application of the tie.  The design must be supported by manufacturing.

Insulation Squeeze Play

click picture for detail

Article Reference ID: DYK00004

Did you know that the Radio Equipment Directive (RED) requires Low Voltage Directive (LVD) compliance without regard to voltage?

Discussion:  RED 2014/53/EU paragraph 3 calls for LVD compliance and does NOT exempt equipment operating at less than the specified 50 or 75 V lower threshold.  Selecting an appropriate standard for the evaluation is not defined in the directive so a lot of questions regarding the evaluation standard are asked.  Many have arbitrarily chosen to use 60950-1 because the wireless feature places this into communications or the associated information technology category.  However, this may be a poor choice because we are not considering the primary function of the device.  If the primary function is used to determine the evaluation standard without regard to the radio feature, a more appropriate standard would be used.  For example, a medical device with a radio is still a medical device and 60601-1 (et al) would be appropriate – just don’t omit adding the radio back into the evaluation to assess RF exposure and other elements regarding RF safety.


Article Reference ID: DYK00005

Did you know that coin batteries can provide a Hot Pocket?

We are reminded every day during electrical safety evaluations that battery implementation requires paying attention to the details as our battery technology webinar series instructed.  But a little bit of info caught my attention during the webinars as a reminder about the coin batteries we encounter frequently.  We are so accustomed to these items that we forget about safety – danger associated with ingestion by small children and the ever familiar I’ll take it along so I can make sure I get the right replacement – taking along by tossing into a trouser pocket with loose change to have the change make a connection across the terminals resulting in a Hot Pocket  – just a reminder.

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Article Reference ID: DYK00012