Crane Scale Capacity vs Accuracy: What Do 3,000 kg and 0.5 kg Mean?

Capacity and accuracy answer different questions: capacity limits the total suspended load allowed through the scale, while stated accuracy describes how closely its reading is intended to represent that load. A 3,000 kg scale is worth considering only when both figures suit the task. This guide gives one comparison table to help you judge the two figures without confusing either with tare, calibration or legal approval.

Additional manual details: The supplied OCS manual lists kg, lb and N unit selection, Hold, Zero/Tare, display-brightness adjustment, Add/totalisation and Inquiry for the last 10 weighing records. It gives a 3–7 second reading-stabilisation time and a -10°C to 40°C service-temperature range. These are manual-stated operating details; follow the supplied instructions for the exact unit.

What does rated capacity control?

Rated capacity is the scale's load boundary, not a target operating weight. For the P6, the confirmed rated capacity is 3,000 kg. That boundary applies to the total suspended load passing through the scale, so it is not limited to the item that an operator intends to weigh.

Any lifting accessories or other items suspended below the scale contribute to that total. Taring a container or attachment may remove its displayed contribution from a net reading, but it does not remove its physical load from the scale. The total passing through the scale must remain within the rated capacity.

The scale rating also does not establish the capacity of the complete lifting arrangement. The crane or hoist, lifting point, scale, shackles or other connections and the load attachment each need an appropriate rating for their own role. The lowest applicable limit and the authorised lifting plan still govern the arrangement.

Do not select a 3,000 kg model merely because the expected load is described as three tonnes. Establish a credible maximum total suspended load for the actual task, including attachments and foreseeable variation, then compare that figure with the ratings and controls used by your organisation. This article does not prescribe a fixed safety margin.

What does stated accuracy tell you?

Accuracy concerns reading performance, not how much weight the scale may carry. The P6 has a stated accuracy of 0.5 kg. This figure should be read exactly as stated: it is not a claim about display division, a calibration result, a certificate or approval for a regulated weighing purpose.

The practical question is whether a 0.5 kg stated accuracy is suitable for the decision you need to make. A broad internal load check may tolerate a different level of uncertainty from a process that separates closely spaced weight bands. Write down the smallest difference that would change your action before assessing the scale.

Context matters as well. The stated figure does not replace a site method for checking condition, zero, stable load presentation and any verification or calibration evidence the organisation requires. If the decision depends on traceable measurement performance, request the relevant documentation rather than assuming the published accuracy statement supplies it.

Where weight determines a price or another regulated transaction, do not infer suitability from either 0.5 kg or a CE mark. Start with the intended legal use and the evidence it requires. The separate guide to internal checking and legal-for-trade weighing explains that purchasing boundary.

How should the two figures be compared?

Use both figures as separate gates. Capacity asks whether the physical load stays within the permitted boundary. Accuracy asks whether the reading is sufficiently informative for the decision. Passing one gate cannot compensate for failing the other.

This comparison prevents a common procurement error. A scale may have ample capacity but insufficient measurement evidence for the intended decision. Conversely, a suitable accuracy statement does not make an under-rated scale acceptable for a heavier total suspended load.

Why does tare not create extra capacity?

Tare changes the displayed relationship between gross and net weight; it does not make a suspended container, sling or attachment physically disappear. If a 200 kg item below the scale is tared, that 200 kg still loads the scale even when the display is set to show zero before material is added.

For that reason, capacity decisions must use gross suspended load rather than the displayed net result. Keep the capacity calculation separate from the operational reason for using tare. Follow the manufacturer instructions and the site's authorised procedure for the controls rather than treating tare as a way to extend the range.

The P6 includes Tare, Hold, Zero and kg/lb selection. Those functions can support a defined reading workflow, but none changes the 3,000 kg capacity. Hold does not prove that a load was stable, Zero does not verify calibration and changing units does not alter the scale's physical limits.

When is the P6 not suitable?

Do not choose the P6 when the credible total suspended load may exceed 3,000 kg, when a 0.5 kg stated accuracy does not support the decision, or when required calibration or legal approval evidence has not been confirmed. Another scale or weighing method may be more appropriate even if one P6 figure appears suitable.

Physical fit is a separate qualification. Capacity and accuracy cannot tell you whether the upper lifting ring, lower hook, connection path, installed length and available headroom fit the existing arrangement. Record those details before ordering and use the hook, ring and headroom checks for the next assessment.

The P6 may suit internal suspended-load checking where the 3,000 kg boundary, 0.5 kg stated accuracy, physical interfaces and required documentation have all been reviewed. For the wider selection process, see the 3 tonne crane scale buying guide.

Frequently asked questions

Is 0.5 kg the display increment?

No. The confirmed product information describes 0.5 kg as stated accuracy. It should not be relabelled as display division, resolution, calibration uncertainty or legal metrology approval without separate evidence.

Can I tare an attachment and then weigh 3,000 kg of material?

Not on that basis. A tared attachment still contributes to the total suspended load through the scale, so the attachment and material together must remain within the 3,000 kg rated capacity.

Does a CE mark confirm weighing accuracy?

No. A CE mark does not by itself establish calibration status, legal-for-trade approval or suitability for a particular measurement decision. Confirm the evidence required for the intended use separately.