Oh this brings back memories....I performed "smoke removal system" special inspections for all Lowe?s west of the Miss. for many years. The fire protection company I worked for until recently engineered these systems for all new Lowe?s stores for nearly 10 years now.
The pics by iwire are of the Vitalink power cable which is -2-hour rated.
http://www.vitalinkcable.com/PDF/VitaLink MC Brochure.pdf
The cable is supposed to home run from the control panel to the exhaust fan without splices. However if a splice is needed, a special ceramic terminal block is required. If exposed to flame the ceramic block fuses the connection leaving it intact to retain the 2-hour rating.
The intent of the smoke exhaust fans are for manual smoke overhaul only and is not a "smoke-control system". The smoke exhaust fan design includes Early Suppression Fast Response (ESFR) sprinklers, and are an alternate design in lieu of smoke and heat vents. The end result is the responding fire department arrives within minutes of a reported fire, the fire is suppressed by the ESFR sprinklers and the smoke removal fans are manually activated by FD personnel, smoke is removed from the store within 10 minutes. This design also alleviates putting holes in the roof.
Lowe?s and other big box whse?s use these systems due to their reliability and performance.
The exhaust fans are high temp rated, dual drive belts and move a minimum 25K cfm each. That?s right, when all 5 fans running there is 125-140 thousand cfm of air exhausting the store. Some larger stores have 6 fans.
I commissioned a couple 1million sq ft + whse?s in Redlands Cal that had (if memory serves) 64 of these fans?