The electrical path.
THE SEQUENCE
Supply enters the building Switchgear distributes it Uninterruptible supplies condition it and provide bridging power Distribution reaches each rack Power distribution units in the rack feed each device Each device has one or more power supplies
WHY EACH STAGE MATTERS
A failure at any point affects everything downstream of it.
WHAT REDUNDANCY LOOKS LIKE
Two independent paths, from supply to device.
WHAT THAT REQUIRES
Equipment with two power supplies, each fed from a different path.
WHAT SINGLE-SUPPLY EQUIPMENT NEEDS
A transfer switch, which selects between two feeds.
WHY THAT MATTERS
Otherwise maintenance on one path takes the equipment down.
WHAT TO CHECK
Whether both feeds are genuinely independent, all the way back.
WHAT DEFEATS IT
Two feeds sharing a single upstream component.
WHAT TO PLAN
Load balanced across both paths, so either can carry everything alone.
WHY
If each path carries half and one fails, the other must take the whole load.
