{"id":6257,"date":"2026-11-13T19:45:41","date_gmt":"2026-11-13T17:45:41","guid":{"rendered":"https:\/\/inteq.lt\/kabelio-ivore-riebokslis-m-pg-parinkimas\/"},"modified":"2026-11-13T19:45:41","modified_gmt":"2026-11-13T17:45:41","slug":"kabelio-ivore-riebokslis-m-pg-parinkimas","status":"publish","type":"post","link":"https:\/\/inteq.lt\/en\/kabelio-ivore-riebokslis-m-pg-parinkimas\/","title":{"rendered":"Cable gland: how to choose by thread M, PG and cable diameter"},"content":{"rendered":"

A cable gland (also called a cable entry or cable fitting, cable gland<\/em>) holds the cable in the enclosure opening, seals it against dust and water, and prevents the cable from being pulled out. An incorrectly chosen gland either fails to seal, fails to tighten, or simply does not fit the opening. Most mistakes come from two things: thread<\/strong> (metric M or older PG) and cable diameter<\/strong>. This article explains how to choose correctly and how to read the gland code.<\/p>\n

What you need to know before choosing<\/h2>\n
    \n
  1. Thread type and size<\/strong> \u2013 M20\u00d71,5, PG13,5 and so on. It must match the opening in the enclosure (a drilled hole or a threaded opening).<\/li>\n
  2. Cable outer diameter<\/strong> \u2013 measure with a calliper, not by the conductor cross-section (mm\u00b2). The same 3\u00d71,5 mm\u00b2 cable can have a different outer diameter from different manufacturers.<\/li>\n
  3. Material<\/strong> \u2013 plastic (polyamide) or metal (brass, stainless steel).<\/li>\n
  4. IP rating<\/strong> and environment \u2013 outdoors, washdown areas, explosive atmospheres (ATEX).<\/li>\n
  5. Is the cable shielded<\/strong> \u2013 if so, you may need an EMC gland that connects the shield to the metal enclosure.<\/li>\n<\/ol>\n

    Metric (M) and PG threads<\/h2>\n

    Modern equipment uses the metric thread<\/strong> with a 1,5 mm pitch: M12\u00d71,5, M16\u00d71,5, M20\u00d71,5, M25\u00d71,5, M32\u00d71,5, M40\u00d71,5 and larger. The first number is the outer thread diameter in millimetres, the second is the pitch. So an M20 gland needs a hole of about 20 mm (the exact size and permitted tolerance are given in the manufacturer's mounting table \u2013 usually the hole is a few tenths of a millimetre larger than the thread).<\/p>\n

    PG thread<\/strong> (German, Panzergewinde<\/em>, DIN 40430) is found in older equipment. Its designation are not<\/strong> diameter in millimetres is the most common mistake. For example, PG7 is 12,5 mm, and PG13,5 is 20,4 mm outer diameter.<\/p>\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n
    PG size<\/th>\nOuter diameter, mm<\/th>\nPitch, mm<\/th>\n<\/tr>\n<\/thead>\n
    PG7<\/td>\n12,5<\/td>\n1,27<\/td>\n<\/tr>\n
    PG9<\/td>\n15,2<\/td>\n1,41<\/td>\n<\/tr>\n
    PG11<\/td>\n18,6<\/td>\n1,41<\/td>\n<\/tr>\n
    PG13.5<\/td>\n20,4<\/td>\n1,41<\/td>\n<\/tr>\n
    PG16<\/td>\n22,5<\/td>\n1,41<\/td>\n<\/tr>\n
    PG21<\/td>\n28,3<\/td>\n1,59<\/td>\n<\/tr>\n
    PG29<\/td>\n37,0<\/td>\n1,59<\/td>\n<\/tr>\n
    PG36<\/td>\n47,0<\/td>\n1,59<\/td>\n<\/tr>\n
    PG42<\/td>\n54,0<\/td>\n1,59<\/td>\n<\/tr>\n
    PG48<\/td>\n59,3<\/td>\n1,59<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n

    PG and M threads are not compatible<\/strong> \u2013 both the diameter and the pitch differ, as does the thread profile. If the opening has a PG thread, an M gland will not screw into it. In that case there are two options: look for a PG gland or use a PG\u2013M reducer adapter. If the opening is simply drilled (no thread) and the gland is held by a locknut, measure the hole diameter and choose a gland whose thread fits exactly \u2013 in an oversized hole the seal may not be reliable.<\/p>\n

    Sealing range \u2013 the most important number<\/h2>\n

    Each gland seals only a cable of a certain diameter \u2013 this is the sealing (clamping) range<\/strong>. Glands of the same thread size can have different ranges, so the thread and the cable are selected separately. Examples from the LAPP SKINTOP ST-M series:<\/p>\n\n\n\n\n\n\n\n\n\n
    Thread<\/th>\nCable \u00d8, mm<\/th>\nProduct<\/th>\n<\/tr>\n<\/thead>\n
    M12\u00d71.5<\/td>\n3,5\u20137<\/td>\nSKINTOP ST-M 12×1,5 (53111000)<\/a><\/td>\n<\/tr>\n
    M16\u00d71,5<\/td>\n4,5\u201310<\/td>\nSKINTOP ST-M 16×1,5 (53111010)<\/a><\/td>\n<\/tr>\n
    M20\u00d71.5<\/td>\n6\u201313<\/td>\nSKINTOP ST-M 20×1,5 (53111020)<\/a><\/td>\n<\/tr>\n
    M25\u00d71.5<\/td>\n9\u201317<\/td>\nSKINTOP ST-M 25×1,5 (53111030)<\/a><\/td>\n<\/tr>\n
    M32\u00d71,5<\/td>\n11\u201321<\/td>\nSKINTOP ST-M 32×1,5 (53111040)<\/a><\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n

    Practical tip: choose a gland whose range puts your cable away from the edges. If the cable is near the lower limit, the gland may not compress enough; near the upper limit, it is hard to tighten.<\/p>\n

    How to decode a gland code<\/h2>\n

    Take LAPP SKINTOP ST-M 20×1,5<\/strong> (order code 53111020):<\/p>\n