Module clamp

A module clamp holds a PV module, or its frame, onto the mounting structure. One installation manual calls for at least four clamps per module, with two on each long side. The end clamps and middle clamps listed in that manual are made of aluminum alloy. Their size depends on the thickness of the module frame. A clamp must not touch the front glass, deform the frame or shade the cells. Tighten it to the torque given by the clamp or racking supplier, and use clamps with toothed contact surfaces for better grip. The main failure mode is bad module clamping, meaning the module is not held firmly enough or the clamp damages the module or frame. It can start during production, installation or operation, and it is found by visual inspection. A badly installed clamp can let modules come loose in high wind or under heavy load. Neighbouring modules share clamps, so one module coming loose can free the next one in a chain. Bad clamping can also cause frame damage, glass breakage and cell cracks, which reduce performance and electrical safety over time. Frameless and glass/glass modules are especially prone to glass breakage from clamps. Common causes are clamps with sharp edges, clamps that are too short or too narrow, clamps placed in the wrong positions and screws that are overtightened. Broken glass lets moisture into the module, which causes corrosion. It also means the module's insulation can no longer be relied on, especially when wet, and it can cause hot spots.

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• sentence 2: support check: partial - Table shows aluminum-alloy for end and middle clamps and sizes vary by frame thickness, but the passages don't explicitly state size depends on thickness beyond the labeled types (reasonably implied).
• sentence 7: support check: partial - Passage supports glass/glass sensitivity and the listed causes, but says frameless modules suffer breakage often rather than 'especially prone', and the 'too short/narrow' and positions causes are covered; minor wording stronger. -->