# Electrical Riser Design Principles ### Issue Image: ## Issue Description: Electrical Service Risers - Where PVC sleeves have been used cast into the slab to allow for future electrical cables or copper pipes to be installed through the slabs ‐prior to the fire rated mastic treatment to these penetrations through the slabs, the PVC sleeves must be removed entirely as the fire rated mastic must be affixed directly to the concrete substrate. - Where the small bell type plastic cast in system is used ‐we would suggest that at the top side of the floor slab, the plastic is cut back some 20‐30mm below the upper slab line so the fire rated mastic can affix direct to the concrete substrate. - No conduits can pass through floor slab penetrations for a fire pillow system ‐only cables are permitted through such system –Care with NBN Conduits. - Metal cable trays cannot pass through fire rated walls or floors and must be cut each side of such fire separating elements so then only the cables are fire sealed. - If the metal cable trays pass through the penetration they spread radiant heat thus must be wrapped with a Promat Firewrap blanket or the like wither side. - Electrical cables should now be wrapped in EDB / Comms risers or main switch rooms ## Actions to Prevent this Issue: - [ ] Builder to review Electrical Riser Passive Fire Design Principles (This article), when review the fire-stopping of electrical risers etc.