Mini rail is also called short rail. It is a kind of solar mounting bracket for metal roof solar mounting structures. It is a so popular bracket to be used in solar mounting systems on tilt tin rooftop. It is widely used in both commercial and residential on grid or off grid solar energy system.

There are mainly two types of mini rails in photovoltaic mounting brackets market. One is narrow version mini rail and the other is wide version mini rail.

The width of narrow version short rail is about 30 mm, length varies from 120 mm to 250 mm . The holes for putting self drilling screws through are in the middle line of this kind of rail .

The width of wide version mini rail is about 57 mm. Length is different from 300 to 400 mm. The holes are allocated in two edges of the ends of mini rail . And the number of holes are usually about 10 pieces.

How to choose the right mini rail for your metal roof solar mounting system ? It depends on the shape of the metal roof sheets. If the metal roof sheet is trapezoidal shape, then we can choose narrow version mini rail as there is a long small flat on the ridge of the sheet. This kind of mini rail can be fixed on the flat ridge of metal sheet by driving self drilling screws through the holes into the roof . EPDM pads should be under the holes in order to protect roof from water in. If use this kind of mini rails, horizontal installation is the only choice.

If the shape of roof is trapezoidal or wave shape, we can use wide version mini rail. We put mini rail spanning the ridges of metal sheet and use st6.3&25 mm self drilling screws to fix it . The EPDM should be stuck under the holes to prevent from water infiltration. If you use wide version short rail, then the panel installation direction should be vertical only.