DIYbanter - View Single Post - Thermostat/low volt wire that is CL2 and direct burial rated?

Bud--

wrote:
On Jun 14, 4:34 pm, ddl@danlan.*com (Dan Lanciani) wrote:
In article , writes:

| I've searched high and low online and can't find any wire that will
| meet code. Everything that is CL2 or CL2X rated, eg thermostat cable
| is NOT rated for direct burial. And anything that is rated for
| direct burial, eg irrigation/sprinkler cable, is NOT rated CL2.

Google Cable Substitution Chart. You can almost always use a variety of
CM cable where you can use CL2, and CM cable is available with a wider
range of characteristics.

Dan Lanciani
ddl@danlan.*com

Thanks for all the input guys. I think I've figured out what to
do. I'm going to use CL rated thermostat type cable in the attic
from the relay over to a new small junction box located inside the
attic by the eaves. Inside the box I'll transition from that CL
cable to sprinkler cable that is underground rated. From there it
will go directly outside, secured with cable ties to the back of a
2"PVC pipe, down to the ground, where it will get buried for the last
7 feet to the pool controller.

My reading of 725 is that it wants conventional wiring or CL or CM or
maybe PTLC. Don't think sprinkler cable is one of them. But it seems
entirely reasonable with the circuit having class 2 protection. (If the
inspector doesn't agree, sprinkler cable would, of course, be entirely
unreasonable.)

About 25 years ago, before the code came up with CL wiring, the class 2
source was considered to protect about anything (except in Twayne's
world). Seems excessively restrictive now.

AFAIK from reading the codes, that should meet all the requirements.
It turned out better from cable availability in reasonable lengths/
prices and also ultimately a single cable would have to go to 2
different locatons, so I can just split it off at the attic box.

The only remaining thing I'm left wondering about is how deep does it
have to be underground? There is nothing in NEC 725 about it
specific to Class 2 power limited circuits that I could find. Since
it's only 7 ft, I guess I'll just make it 2ft and then I'll be OK for
sure, but clearly they route similar sprinkler cable from controllers
inside houses to underground and only bury them 6" or even less.

IMHO the consideration is system reliability.

--
bud--