How much Clearance in Rear for Front Access Only Switchboard

[stcalle]

I understand for a front and rear access swithboard, you would follow the NEC Article 110 to come up with the proper working clearances for the front and back.

But, for a front access only switchboard I was thinking you can have it up closer to a wall but would leave the manufacturer recommended clearance in the back. Is this usually the case or is there a larger amount of space usually required to be kept in the back for front access only equipment?

Would this also be true for transformers, meaning I can have a transformer's rear up against a wall but would leave the manufacturer's recommended clearance in the back?

Thanks

 

[infinity]

A front access switchboard would require no clearance in the rear unless the manufacturer stated a specific distance.

A vented transformer would have a similar requirement where you would follow the manufacturers specified distance.

450.9 Ventilation. The ventilation shall be adequate to dis-
pose of the transformer full-load losses without creating a
temperature rise that is in excess of the transformer rating.
Transformers with ventilating openings shall be installed
so that the ventilating openings are not blocked by walls or
other obstructions. The required clearances shall be clearly
marked on the transformer.