Two quite different audiences search for the answer to this question, and the answer differs significantly for each.
On a construction site, the capacity of a lifting chain determines whether a sling is legally compliant and safe for the task. In a powerlifting gym, it determines how much load a barbell chain contributes to the lift. The variables, the standards, and the consequences are entirely different in each.
For an industrial chain, the weight it can hold depends on four factors: steel grade, wire diameter, the number of legs in the rigging configuration, and the angle each leg makes under load. Adjust any one of those, and the rated capacity changes. For a gym chain, capacity is a matter of mass per pair and the number of links that leave the floor during the lift.
This piece covers both. All figures are sourced, and the compliance requirements for UK lifting operations are treated as non-negotiable throughout.
Industrial Chains: What Governs Capacity
Chain Grade
Grade is the single most consequential factor in determining how much weight a chain can hold. In the UK, only Grade 80 and Grade 100 are approved for overhead lifting, both manufactured from heat-treated alloy steel to BS EN 818-2.
Grade 80 (G80) is the standard for most industrial applications. Grade 100 (G100) carries approximately 25% more load than G80 at the same wire diameter, which means a G100 assembly can achieve the same rated capacity with fewer legs or a lighter overall rig. The difference is meaningful where headroom is limited or where reducing sling weight matters to the team.
Grades 30, 43, and 70 are not approved for overhead lifting regardless of diameter. Grade 70, in particular, causes procurement errors because it superficially resembles Grade 80. The distinction is the gold zinc-plate finish on the transport chain versus the yellow or red paint on the lifting chain. Using any sub-Grade 80 chain in a lifting application is a breach of LOLER 1998 and carries significant legal exposure for the duty holder.
Wire Diameter and the Safety Factor
Diameter governs the cross-sectional steel area, and cross-sectional area governs capacity. The relationship is not proportional: doubling the diameter more than doubles the WLL because the cross-sectional area scales with the radius squared. A 16 mm chain does not carry twice the load of an 8 mm chain. It carries considerably more.
All WLL figures are calculated at a 4:1 safety factor in accordance with BS EN 818-2. The minimum breaking load is four times the published WLL. The WLL itself represents the maximum load applicable under normal operating conditions and must never be treated as a ceiling to work against.
Grade 80 and Grade 100 Chain Capacity Table
Single-leg WLLs at 0° (vertical lift). Multi-leg configurations and non-vertical angles reduce effective capacity per leg; see the angle section below.
|
6 mm |
1,120 kg |
1,400 kg |
|
7 mm |
1,500 kg |
1,900 kg |
|
8 mm |
2,000 kg |
2,500 kg |
|
10 mm |
3,150 kg |
4,000 kg |
|
13 mm |
5,300 kg |
6,700 kg |
|
16 mm |
8,000 kg |
10,000 kg |
Verify all figures against the certificate supplied with the specific assembly. Generic tables are a reference, not a substitute for manufacturer documentation.
How Sling Angle Reduces Capacity
A single-leg sling lifting directly below the hook applies the full rated WLL. Add a second leg and the geometry changes immediately. Each leg now pulls at an angle rather than straight down, which increases the tension in each leg relative to the load being suspended.
The angle factor is expressed as the deviation of each leg from the vertical. The LEEA and HSE publish factor tables; the figures below reflect the load on each individual leg as a percentage of the single-leg WLL:
|
0° (vertical) |
100% |
|
15° |
97% |
|
30° |
87% |
|
45° |
71% |
|
60° |
50% |
At 60° from vertical, each leg in a two-leg sling is carrying the equivalent of the full single-leg rated load at only 50% of its published capacity. A four-leg G80 sling at 60° carries significantly less than four times the single-leg WLL.
Rigging teams who work from leg count alone, without applying the angle factor, routinely overload individual legs without knowing it. This is one of the most consistent sources of chain overloading on UK sites. When the angle is uncertain, calculate from the worst case and size up accordingly.
What Else Reduces a Chain's Effective Capacity
A chain's published WLL assumes it is in the condition and configuration for which it was certified. Several site factors cut below that figure without any physical change to the chain.
Wear
Chain links shed diameter through repeated contact with hooks, shackles, and hardware. The standard discard threshold is 90% of the nominal new diameter. For a 10 mm chain, that is 9 mm. A chain worn to that point carries materially less than its rated WLL, and the certificate that shipped with it no longer reflects its actual condition. Measure. Do not estimate.
Temperature
Grade 80 and Grade 100 alloy chains operate without capacity reduction over the temperature range of −40°C to 200°C. Above that threshold, the manufacturer's derating specification applies. Foundries, steel plants, and casting facilities regularly exceed that threshold. Chains in those environments need explicit temperature verification before use.
Shock Loading
WLL figures are calculated for static loads under controlled conditions. A load that drops and is arrested by the chain, or one that swings and jerks mid-lift, generates dynamic forces well above the suspended weight. No WLL covers shock loading. Any lift that involves dynamic forces requires a more conservative chain specification than static weight alone would suggest.
Kinking and Cross-Loading
A kinked or twisted chain concentrates stress at the deformed link. Once deformation is confirmed during inspection, the chain is taken out of service. Straightening a kinked link does not restore its original geometry or capacity.
Chains for Weightlifting: A Different Set of Variables
Weight-lifting chains operate on an entirely different principle. They are not rated for overhead lifting and must never be used in a rigging context. Their function is to accommodate resistance: as the barbell rises, links progressively clear the floor, and the total chain weight increases. The load at the top of the lift is heavier than at the bottom, which matches the natural strength curve of most compound movements.
A standard pair of training chains typically weighs 15-30 kg. Individual links contribute roughly 0.5-1 kg as they lift off the floor. By the time the bar reaches the top of a bench press or squat, most links have cleared the surface. The practical load addition per chain at that point is approximately 10-20 kg, depending on chain length and setup.
Chains for weightlifting are selected by total mass and link size. They are manufactured from carbon steel rather than heat-treated alloy steel used in lifting applications, and they carry no LOLER certification. Industrial lifting chains can be used as gym chains, but their stiffness and link geometry make them poor training equipment. They are built for rigging, not for hanging from a barbell sleeve.
Weight lifting with chains follows a consistent setup: a leader chain and carabiner hang the main chain from the barbell sleeve. At the bottom of the lift, most links pool on the floor. As the bar ascends, links lift progressively, adding weight gradually through the range of motion. That progressive loading is the training stimulus; a fixed-weight plate provides no such effect.