Does anyone know what this device is?
It was installed on each phase of a 3ph 4160V switch, but the date code on the mysterious device indicates it was not part of the original installation.
Is it possible that the face might display a flag (as in a colored indicator that can swing into view)?
I've seen similar looking devices installed (both permanently and temporarily for cable troubleshooting). They are fault current indicators, which flip a flag into view if the cable current exceeds some value. They are reset by lower currents flowing for a few seconds.
When troubleshooting large systems (underground distribution, for example) putting these on several cable sections can assist in identifying which one is faulted.
There might be what appears to be two metal pins protruding from behind the cylindrical enclosure (near the cable window). The JPEG is sort of blurry, but if that's what they are, these might be a CT-burden combination into which someone can connect load monitoring equipment.
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