GX16 vs GX12 vs LD16: Aviation Connector Size and Pin Chart

Search for any circular industrial connector and you will meet three names for what looks like the same product: GX16, GX12, и LD16. Buyers ask for one and get quoted another, then discover the flange hole they drilled does not fit. The confusion is real and it has a simple cause: GX12/GX16 are the traditional Chinese-standard naming for threaded circular connectors, while LD and SD describe modern moulded-shell series that use the same mounting footprint but a different locking and sealing construction.

This guide gives you the dimension and pin-count tables for each family, the mounting-hole sizes you actually need to drill, and a decision path for choosing between them. All figures refer to the common 2- to 12-pin industrial grades; audio-market versions of “GX16” follow different dimensions and should not be mixed into industrial panels.

Quick Answer: Which Series Fits Your Panel

The practical takeaway from the table: GX12, GX16, LD16 and SD16 all mount in the same 12 mm or 16 mm panel hole. The differences are the shell material, the sealing system, and how much current the contact cluster tolerates. That is why a buyer who designed a panel around “a GX16” can usually accept an LD16 as the delivered part — and why the substitution must still be confirmed, not assumed.

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GX Connector Sizes: The Dimension Chart

The GX family is named by its shell thread size in millimetres. Everything else — panel hole, gland range, contact capacity — scales from that number. The table below lists the sizes that appear in industrial purchasing, with the dimensions that decide whether a connector fits your enclosure.

Three dimensions cause nearly all field problems:

• Panel cut-out. The flange behind the thread needs a hole of 16.2–16.5 mm for GX16. Drill 16.0 mm and the connector will not seat; drill 17 mm and the O-ring cannot compress. A step drill or a 16.5 mm hole saw gives a cleaner edge than a punch on thin sheet.
• Thread engagement. The locking ring needs at least three full turns on the mating shell. Bulkheads thicker than about 3 mm with paint or powder coating can leave too little thread — either deburr the coating or specify the longer-thread variant.
• Cable gland range. GX16 accepts roughly 4–8 mm cable OD. A cable at 9 mm will not pass the rear gland; forcing it destroys the strain relief before the connector is ever mated.

GX12 vs GX16: what actually changes

The two sizes differ in more than diameter. GX12 carries fewer pins (up to 7) and smaller contacts, which caps continuous current around 3–5 A for the common pin layouts. GX16 with 8 pins or fewer typically carries 5–10 A depending on the supplier’s contact plating and the pin diameter used. If your load is a 24 V sensor or a valve solenoid, GX12 is usually enough and saves panel space. If you are feeding a small motor, a heater band or a light bar that draws several amps, GX16 is the safer default and costs only a few cents more.

One more practical difference: because GX12’s shell is smaller, its solder cups are tighter. Field-wiring 1.5 mm² conductors into a 7-pin GX12 is awkward; GX16 handles 1.5 mm² comfortably in most pin counts. For serviceable panels — anything a technician may rewire — the larger shell pays for itself.

Pin Count Charts: 5-Pin, 8-Pin and 10-Pin Layouts

Pin count is where ordering mistakes concentrate, because the same model number covers very different internal layouts. The industry convention arranges pins in rings: a centre pin for the first, then an inner ring, then an outer ring. The table shows the common industrial arrangements.

Why 5-pin dominates search. Five pins is the natural layout for a three-phase signal pair plus earth, for a stepper motor (two coils = four wires + shield), and for countless 4-wire sensor plus drain combinations. If you are standardising a panel on one pin count and have no reason otherwise, 5-pin GX16 is the most widely supported and the easiest to source replacement parts for.

Solder cup vs screw terminal

GX12/GX16 connectors ship in two termination styles. Solder cups suit factory looms: a trained assembler, a temperature-controlled iron, and heat-shrink over each joint. Screw-terminal rear shells suit field service: no soldering iron on site, wires under a screw, done in minutes. If your maintenance team will ever re-terminate in the field, order the screw-terminal version even if the unit price is higher — the alternative is cutting back a moulded loom.

Where LD16 and SD16 Fit: Same Hole, Different Shell

Сайт LD16 series aviation plug keeps the M16-class mounting footprint of a GX16 but replaces the all-metal screw shell with a moulded body and an integrated sealing cap. That construction change buys three things a bare GX16 does not have:

• Sealed unmated state. A GX16’s exposed flange socket collects dust and water when the plug is pulled. LD/SD caps close over the receptacle, so an unmated outdoor connection stays serviceable.
• Strain relief that is part of the shell. Instead of a small rear gland, the moulded body clamps a wider cable range and resists torsion better on moving looms.
• Corrosion behaviour. Nickel-plated brass GX shells survive indoors indefinitely but pit in coastal or chemical atmospheres; the engineering-plastic bodies of the LD series do not corrode at all.

Сайт SD16 aviation cable connectors push the same idea further with IP-rated sealing on both plug and socket, aimed at outdoor cabinets, agricultural equipment, and marine-adjacent installations. For a comparison of the sealed ranges, the SD13 (M13 footprint) and SD20 (M20 footprint) cover the panel sizes on either side of 16 mm.

Substitution rules: when LD16 can replace a GX16

The rule that matters most is the third row: LD and SD plugs do not mate with GX sockets, even though the panel holes match. If half your plant is wired with GX and you want to standardise on LD, plan the changeover per complete connection pair — plug plus socket together.

Choosing in 60 Seconds: A Decision Path

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1. Measure the current per pin, not the total. A 10-pin connector does not carry 10 × its single-pin rating on one pin. If any conductor exceeds 8 A continuous, step up to GX20/GX25 or a dedicated power contact layout.
2. Count pins, then add one spare. Retro-fitting a pin later is impossible on solder-cup shells; a spare position costs nothing today and saves a loom rebuild.
3. Check the environment. Dry indoor panel → GX12/GX16. Dusty, wet, outdoor or washdown-adjacent → LD16/SD16 with sealing caps.
4. Fix the panel hole before ordering. 12.5 mm or 16.5 mm, deburred, coating cleared from the sealing face.
5. Match plug and socket as a set from one supplier. Mixing brands across the mating interface is the single most common cause of intermittent contact resistance in these families.

Часто задаваемые вопросы

Is GX16 the same as XLR?

No. XLR is a latching audio connector with a different shell and contact system. Some audio-market products are sold as “GX16” but follow XLR-like dimensions. Industrial GX16 is a threaded M16×1 connector; buy from industrial suppliers and check the dimension table before drilling.

What current can a 5-pin GX16 carry?

Typically 5 A per pin continuous for standard contacts, with some suppliers rating 10 A on larger-diameter pins. De-rate if the loom is bundled, inside a hot enclosure, or at altitude — the same thermal derating logic that applies to any connector applies here.

Can I mate a GX16 plug with an LD16 socket?

No. The panel cut-outs are the same but the thread profiles, keyways and contact systems differ. Always replace plug and socket as a pair.

Which is better for outdoor use, GX16 or SD16?

SD16 (or LD16 with sealing caps) — the moulded shell and caps keep water and dust out of the contacts both mated and unmated. A bare metal GX16 relies on the thread joint alone and has no unmated protection.

What hole size do I drill for a GX16?

16.2–16.5 mm for the standard flange. Clear paint from the sealing face and debur the edge so the O-ring seats flat.