Do people changing abrasive wheels that operate inside machines (e.g. behind fixed guarding) need to be trained to change them?

My instinct is yes as all the guidance I have seen doesn't differentiate between types of abrasive wheel.

However I have been informed that people don't need to be trained because of the extra safeguards (by the site based h&s manager).

Opinions (with explanations backing them up) welcome!

The old requirement for "training" under the abrasive wheels regs has gone - the obligation now is to ensure that people doing a job (any job) are competent to do it...

A badly mounted wheel (of the abrasive particle bound in a matrix type) may shatter or it may run out of balance and break the shaft... Either of which could cause serious damage inside any enclosure and / or injury if bits can escape past or through the enclosure...

A competent person is one who knows what to look for, how to recognise it when he sees it and what to do about when he sees it.

For an abrasive wheel - a competent person will know why the spindle speed is important, why the balance is important, how to balance and trim the wheel, what clearances are required from workpieces and rest/guards etc and how to spot and rectify most common defects. This knowledge may be gained from formal certificated 'training or education' or it may (just possibly) be gained from sitting with Nelly. But if there is no record of the knowledge transfer (e.g a training certificate) it may be difficult to prove in court that the employer was justified in considering the employee to be 'competent'