Strathead
Senior Member
- Location
- Ocala, Florida, USA
- Occupation
- Electrician/Estimator/Project Manager/Superintendent
I reviewed three past threads all the way back to 2011 and they don't specifically answer this question...
First here is the code section (and the appendix clarification):
12.3.7* Class A and Class X circuits using physical conductors (e.g., metallic, optical fiber) shall be installed such that the outgoing and return conductors, exiting from and returning to the control unit, respectively, are routed separately. The outgoing and return (redundant) circuit conductors shall be permitted in the same cable assembly (i.e., multi-conductor cable), enclosure, or raceway only under the following conditions:
(1) For a distance not to exceed 10 ft (3.0 m) where the outgoing and return conductors enter or exit the initiating device, notification appliance, or control unit enclosures
(2) For single raceway drops to individual devices or appliances
(3) For single raceway drops to multiple devices or appliances installed within a single room not
exceeding 1000 ft2 (93 m2) in area
A.12.3.7 A goal of 12.3.7 is to provide adequate separation between the outgoing and return cables. This separation is required to help ensure protection of the cables from physical damage. The recommended minimum separation to prevent physical damage is 12 in. (300 mm) where the cable is installed vertically and 48 in. (1.22 m) where the cable is installed horizontally.
My focus is on parts (1) and (2) of 12.3.7 and what the distinction is between them. I think that per #2 could run a single conduit with incoming and outgoing conductors 15 feet horizontally and down the wall 14 feet (or basically any distance) as long as it is terminated in a single device with no other outgoing conductors.
Where #1 would come in to play would be if I was running from a junction box to to first device and then extending on to another device in another room (to avoid reference to #3). So, say I have back to back strobes in two bathrooms. I would run one conduit with 4 conductors to the first device and a short stub to the second device. But even if that is true exactly where does the rule work? Is the ten feet in this application a combination of both conduit runs, or does each device get 10 feet of shared conductor?
Another application where I think rule one would be typical is a drop that has a horn/strobe and then directly below it a pull station. I assume this is a perfect example of where the 10 feet comes in to play. I will either need to separate incoming and outgoing or run a drop per device because the job I am envisioning has 22 foot open ceilings.
First here is the code section (and the appendix clarification):
12.3.7* Class A and Class X circuits using physical conductors (e.g., metallic, optical fiber) shall be installed such that the outgoing and return conductors, exiting from and returning to the control unit, respectively, are routed separately. The outgoing and return (redundant) circuit conductors shall be permitted in the same cable assembly (i.e., multi-conductor cable), enclosure, or raceway only under the following conditions:
(1) For a distance not to exceed 10 ft (3.0 m) where the outgoing and return conductors enter or exit the initiating device, notification appliance, or control unit enclosures
(2) For single raceway drops to individual devices or appliances
(3) For single raceway drops to multiple devices or appliances installed within a single room not
exceeding 1000 ft2 (93 m2) in area
A.12.3.7 A goal of 12.3.7 is to provide adequate separation between the outgoing and return cables. This separation is required to help ensure protection of the cables from physical damage. The recommended minimum separation to prevent physical damage is 12 in. (300 mm) where the cable is installed vertically and 48 in. (1.22 m) where the cable is installed horizontally.
My focus is on parts (1) and (2) of 12.3.7 and what the distinction is between them. I think that per #2 could run a single conduit with incoming and outgoing conductors 15 feet horizontally and down the wall 14 feet (or basically any distance) as long as it is terminated in a single device with no other outgoing conductors.
Where #1 would come in to play would be if I was running from a junction box to to first device and then extending on to another device in another room (to avoid reference to #3). So, say I have back to back strobes in two bathrooms. I would run one conduit with 4 conductors to the first device and a short stub to the second device. But even if that is true exactly where does the rule work? Is the ten feet in this application a combination of both conduit runs, or does each device get 10 feet of shared conductor?
Another application where I think rule one would be typical is a drop that has a horn/strobe and then directly below it a pull station. I assume this is a perfect example of where the 10 feet comes in to play. I will either need to separate incoming and outgoing or run a drop per device because the job I am envisioning has 22 foot open ceilings.