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Testing Completed for 61010-1 and 61010-2-030

Yesterday we performed the final set of tests for the Mooshimeter for 61010-1 and 61010-2-030 compliance.  The modified housing passed as a CAT III 600V device, and now it is (hopefully) just paperwork from here forward.  I want to share a little about this part of the Mooshimeter’s journey, as it is the largest unforseen stumbling block we’ve hit.

What Exactly Did We Test?

In the manual, there is a rating that indicates that the Mooshimeter is only rated to make measurements within 600V of Earth Ground.  This sounds like a weird or counterintuitive rating; since the device is both battery operated and wireless it shouldn’t “care” where it is with respect to the Earth Ground.  However, it can be used as a handheld device and therefore there is a potential path to earth ground through the user.  This path is blocked by “reinforced insulation”, which means that it is rated to continue to provide adequate protection even if one layer of protection is compromised.

As I said in my earlier post, we had issues with the housing dielectric withstand test, which is the set of tests to verify that portion of the reinforced insulation.  The device is preconditioned in a humidity chamber for 48 hours, allowed to rest 2 hours, and then wrapped in tin foil as shown below.  A test voltage is applied between the input terminals and the foil for 5 seconds to test transient immunity and another voltage is applied for 60 seconds to test steady state immunity.

Housing Dielectric Test Setup

Housing Dielectric Test Setup

For reference, here are the voltages and durations applied for three different potential safety ratings:

5 Second

60 Second

CAT III 600V

5400

3600

CAT II 600V

3510

3600

CAT III 300V

3510

3000

Note that for CATII 600V the 60 second test is done at a higher voltage than its 5 second test.  Weird…

Results

The modified housing passed both of the CAT III 600V tests.  Here is the modified housing passing the 5400VAC test.  It is a bit boring, which is a very good thing:

I left out the videos of the 60 second tests as they are completely uneventful.

The unmodified housing passed the 3600VAC RMS test, but failed the 5400V test 1 or 2 seconds in.  Here is the video of the test failure:

The really interesting part is that the failure was not immediate.  This means that it is on the hairy edge of a pass, which may explain why it did pass when it was tested without humidity preconditioning.

Lessons Learned

This test exposed an area of our design that was marginal.  We’ve chosen a conservative path in solving the issue, and I feel extremely confident in the safety of the modified design.

Here is what I learned:

  1. There are many different safety standards that apply to different types of devices, and that each of these standards have tests that are similar to but subtly different than the tests in the other standards.  In some cases, familiarity with these other standards proved to be a liability when that prior knowledge predisposed us towards assumptions that are true in one standard and false in another.  The dielectric housing withstand test in particular is subtly different for measurement equipment, medical equipment, and IT equipment.
  2. Carefully plan the order of your tests, and have backups ready.  Each test stresses the material, weakening it for future tests.  A failed test makes that particular sample unusable for future testing.  Therefore you have to strike a balance between being conservative (easy tests leading up to harder tests) and aggressive (hardest test first).  Having multiple DUTs alleviates this.
  3. 3d printers and dielectric testing don’t mix well.  FDM based printers leave voids in the model that severely compromise its electrical integrity.  Our SLA didn’t have appropriate resins available.

6 Responses to “Testing Completed for 61010-1 and 61010-2-030”

  1. Beat August 1, 2014 at 7:26 pm #

    Congratulations for well-deserved passed test !

    And many thanks for being very open about the issues, solutions and lessons you learned in the process.

    It gives me a very good feeling about the security of your device (to the contrary of many low-cost devices that I’m still scratching my head how/if they passed real security tests) and about the professionality of your approach!

    Many Thanks, and now wishing you all the best in entering the manufacturing ramp-ups, which is usually another adventure full of surprises and solutions to find. In the end you will have learned a LOT and you will be having a very solid product of which you can be very proud.

  2. Jeremy October 13, 2014 at 1:55 pm #

    Hey! Very nice product and test report. I am currently working on an isolation circuit board for measuring current and voltages, and am trying to research what the UL safety requirements are. The HV that you posted here, is that from 61010-1 or 61010-2? Are the test values you posted for reinforced insulation? If I am using a CT with my board, then my board could be considered as supplemental insulation? Do you have those values for CAT III, 600V? Thanks!

    • Eric October 17, 2014 at 10:17 am #

      We highly recommend getting the specific standards you are looking to adhere to. There are many tests and regulations in those standards that we haven’t posted about on the blog, as doing so would make for some very dry reading. For every test we’ve described, there are at least ten more we haven’t. Additionally, the specifics depend heavily on the design of the device. We didn’t use a CT, so we did not do any CT appropriate testing on this particular product. I’ve used them in medical products, but those adhere to 60601 instead of 61010.

      If you adhere to 61010, you’ll need to find the correct -2-??? standard for your product. -2-030 is the standard we worked with for the Mooshimeter. The test values posted were from that standard.

      The test houses we worked with were very happy to provide advice and guidance on navigating the safety standards. I would check with them to get their expert opinions.

      • Jeremy October 22, 2014 at 2:18 pm #

        Thanks, what test house did you use?

        • Eric October 25, 2014 at 11:45 am #

          Compliance World Wide for RF and TUV for safety.

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  1. Email Update | Mooshim Engineering - August 1, 2014

    […] successfully completed all safety testing; Expect to see a full report tomorrow on the blog (EDIT: Report published here). The updated Mooshimeter design has passed all relevant tests in 61010-1 and 61010-2-030. The test […]

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