Holding magnets, with their special magnetic circuit design, generate great attraction force, therefore they are used in many places when it is needed to hold something either temporarily or permanently.
As it is right at the upper limit of the part, can we use, for example, a rated 30kg holding magnet to hold a 30kg weight item without any risk that the item might fall?
When we design our holding magnets, we try to have the best combination of magnets and other parts to get the highest possible force. First, we have the basic design with simulation software, and then based on the design we make experiments to get enough data of tested force. The safety factor is particularly considered. We choose the combination that has, at least, 20% higher force than the rated force and we fully act on this principle with each of our products.
Back to that question, a rated 30kg holding magnet could have a tested value of 36kg force so it is safe to hold a 30kg project.
This rule applies to all of our holding magnet: pot magnets, hook magnets, channel magnets, rubber coated magnets, shuttering magnets, etc.