True but since these panels are supplied by service conductors there is usually no ready way to deenergize without the POCO working with you and also the OC protection is limited.
The main buss can't be denergized, presenting a shock and arc flash hazard. How many electricians would have the POCO deenergize power to replace a breaker?
Even with the separate disconnects, still would need a poco deenergization. Line side still hot. Just not as much of a incentive to work hot, Square D iLine is probably the safest, though not recommended, hot swappable. Damaged buss can change all of that in short order. Had a customer that changed to a single main because they didn’t want to schedule with the poco every time they replaced one of the six. After putting in the single service disconnect, found the buss was burnt on the breaker they wanted changed. Removing it hot could have been catastrophic.
I read one where the proposer said MLO's "are longer relevant" - whatever the hell that means. Yet another case of these idiots not taking into account cost with their code changes. On a recent job I did, the cost to go from a MLO to main breaker for a thousand amp mdp would have been twice as much, from about $4,500 to $9000. the existing equipment was way underrated for fault current, and one of the poles on the main breaker didn't open. $4,500 could easily be the difference between them deciding not to upgrade it. Genius move NFPA.
