What should never be connected to a hydrant?

Connecting hard suction to a hydrant is not appropriate because hard suction lines are intended for drafting water from static sources like ponds or tanks, rather than drawing directly from a pressurized water system. These types of hoses are designed to handle suction pressure and are typically used when a fire truck cannot get close enough to a water source to use a supply line.

A hydrant provides high pressure water, and using a hard suction line in this situation could compromise the efficiency and functionality of the hydrant. It might also lead to equipment damage or accidents due to the improper application of a tool that is specifically devised for a different purpose.

Regular hoses, attack lines, and supply lines, on the other hand, are designed for direct connections to hydrants and perform optimally under the pressurized conditions that hydrants provide. Using the appropriate type of hose or line ensures the safety and effectiveness of fire operations.