Failed PAT test on Inno Spot Pro

[RobKennedy]

Hello everyone. I had all my equipment PAT tested today and all was good apart from an issue with an ADJ Inno Spot Pro which I have had for a few years. I have two of them in white and they are great for gobo projection so although I do not use them much they have made their money back.

One of them passed the test no issues but one failed with an earth leakage problem. The engineer mentioned I should get in touch with ADJ and ask if this expected as some devices are prone to higher levels of earth leakage. I'm not that optimistic as one is fine and they have both been fine in previous years testing so something appears to have changed.

Anyway, to get to the point I wondered if anyone else has had similar issues out of interest ?

I'm thinking they will just suggest a new power supply or something, and I'll need to get it sorted as my insurance is not valid without a valid test certificate.

[ppentertainments]

Hello everyone. I had all my equipment PAT tested today and all was good apart from an issue with an ADJ Inno Spot Pro which I have had for a few years. I have two of them in white and they are great for gobo projection so although I do not use them much they have made their money back.

One of them passed the test no issues but one failed with an earth leakage problem. The engineer mentioned I should get in touch with ADJ and ask if this expected as some devices are prone to higher levels of earth leakage. I'm not that optimistic as one is fine and they have both been fine in previous years testing so something appears to have changed.

Anyway, to get to the point I wondered if anyone else has had similar issues out of interest ?

I'm thinking they will just suggest a new power supply or something, and I'll need to get it sorted as my insurance is not valid without a valid test certificate.
Did the tester zero his earth lead just to make sure all is ok at that end as it does seem strange

[Nakatomi]

Your test engineer might just have used the wrong test range for the unit - which the other fixture could have passed & that one didn't - it wouldn't necessarily mean it's not safe. Class 1 appliances like moving heads (metal chassis, metal earth pin on the plug, 3 core cable.. ) can leak up to 75mA before they're deemed a failure on this test. If it'd been tested as class 2 by mistake then the failure limit is only 25mA. It certainly isn't a class 2 appliance though!

Now then - assuming the right test range has been used & it failed because it leaked more than 75mA from live or neutral to earth - then it's more than likely an electrical suppression component is aging & needs to be replaced. This is usually at the mains input stage, either as part of the internal power supply or a secondary unit between the mains input socket and the power supply itself. The most likely suspect is a component called a capacitor. These have a tendency to break down as they get older which is exasperated by heat. It shouldn't be very expensive to fix either way.

The IET code of practice states that the earth leakage test can be used as an alternative to the insulation test. The insulation test verifies that current cannot pass between line (L), neutral (N) and Earth by measuring its resistance. Any resistance measured of 1 million ohms (1M Ohm) or more is deemed a pass. So really it's the insulation resistance test that should've been carried out first if it's a class 1 appliance (made of metal - yes it's a moving head with a metal base & metal parts, has a 3 pin mains input, 3 core cable and has a metal earth pin on the plug). If it fails that, then maybe it's damp inside (a common reason hazers & foggers, bubble machines etc fail this test) or an electrical suppression component inside is aging. That obviously depends on the extent to which it fails. If it's a marginal failure - yeah moisture or whatever but a more extreme failure could mean a live or neutral wire inside is touching the metal of the case.

Now if it was earth bonding then maybe internal corrosion where the earth lead contacts the chassis or simply a loosened terminal or broken wire caused the fail.

First port of call - get a 2nd opinion. Next, get a quote for a fix.

[RobKennedy]

Many thanks for the comments.

I spoke to the tester and he had tested it as the correct class, it's a bit over at just over 1mA.

I'll get it checked out and point them to the power supply as thats the prime suspect.

[Nakatomi]

Many thanks for the comments.

I spoke to the tester and he had tested it as the correct class, it's a bit over at just over 1mA.

I'll get it checked out and point them to the power supply as thats the prime suspect.

1mA.. yeah sounds like a capacitor going leaky to me. They often use capacitors connected to mains earth to help stop electrical noise getting out of the fixture onto the mains. When they get old guess what? they start leaking current down to mains Earth..