Ser through the Attic

[roach1521]

Can I run my SER service cable through the Attic and either support it to the bottom of the roof rafters or just on the floor boards, I'm wondering about protection


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[roach1521]

I meant floor joist not boards

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[petersonra]

I think once it comes inside it can no longer use the 75 deg C rating. Not sure what being in an attic that might be subject to extended periods of time at higher temps might do to the ampacity.

 

[Dennis Alwon]

Can I run my SER service cable through the Attic and either support it to the bottom of the roof rafters or just on the floor boards, I'm wondering about protection


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yes, you can as long as you follow 334.23 which takes us to 320.23

320.23 In Accessible Attics. Type AC cables in accessible attics
or roof spaces shall be installed as specified in 320.23(A) and
(B).
(A) Cables Run Across the Top of Floor Joists. Where run
across the top of floor joists, or within 2.1 m (7 ft) of the floor
or floor joists across the face of rafters or studding, the cable
shall be protected by guard strips that are at least as high as the
cable. Where this space is not accessible by permanent stairs or
ladders, protection shall only be required within 1.8 m (6 ft) of
the nearest edge of the scuttle hole or attic entrance.
(B) Cable Installed Parallel to Framing Members. Where the
cable is installed parallel to the sides of rafters, studs, or ceiling
or floor joists, neither guard strips nor running boards shall be
required, and the installation shall also comply with 300.4(D).

 

[roach1521]

I was reading that this morning, how do I protect it with the "gaurd strip" AKA nail plates, that's what kind of got me

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[roach1521]

I have used the running boards across the floor joists in basement and attached it to the running boards but not really protected

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[drcampbell]

I was reading that this morning, how do I protect it with the "guard strip" AKA nail plates ...

The way I read it, "guard strips" are not even remotely the same thing as nail plates, but are parallel to the cable, immediately adjacent to the cable and run the full length of the cable, so that if someone were to step or grab onto a cable, the guard strips would provide structural support.

 

[hbiss]

I was reading that this morning, how do I protect it with the "gaurd strip" AKA nail plates, that's what kind of got me.

A) Cables Run Across the Top of Floor Joists. Where run
across the top of floor joists, or within 2.1 m (7 ft) of the floor
or floor joists across the face of rafters or studding, the cable
shall be protected by guard strips that are at least as high as the
cable. Where this space is not accessible by permanent stairs or
ladders, protection shall only be required within 1.8 m (6 ft) of
the nearest edge of the scuttle hole or attic entrance.

Guard strips are not nail plates. In your case you would fasten 2x4 lumber on the flat to the joists on both sides of your cable run. The 2" dimension needs to satisfy the "at least as high as the cable" requirement. If your cable is thicker than the 1-5/8" thickness of a 2x you need to add height to the guard strips by adding some 1x4s on top or another 2x4.

-Hal

 

[drcampbell]

... If your cable is thicker than the 1-5/8" thickness of a 2x you need to add height to the guard strips by adding some 1x4s on top or another 2x4.

Or turn it 90°, call it a 4x2 and provide protection for cables up to 3⅝" thick.

 

[roger]

Can I run my SER service cable through the Attic and......

Is this cable actually the service conductors? If it is you will probably have a bigger reason as to why you can't run it through the attic, see 230.70(A)(1)


Roger

 

[roach1521]

Thanks, good stuff

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[Ponchik]

If it is "the SERVICE" cable I would ask the poco to see what they have to say about the installation.

Also look at the code section that Roger posted.

 

[roach1521]

Is this cable actually the service conductors? If it is you will probably have a bigger reason as to why you can't run it through the attic, see 230.70(A)(1)


Roger

This is a sub fed service
, SER cable will be fused on the outside, the wire will have overload protection,

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[roger]

This is a sub fed service
, SER cable will be fused on the outside, the wire will have overload protection,

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Then you have a feeder, not service conductors, see the definition of both.

Roger

 

[electrofelon]

Can I run my SER service cable through the Attic and either support it to the bottom of the roof rafters or just on the floor boards, I'm wondering about protection


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Generally I find it much much quicker to drill holes and pull the cable thru them vs dealing with a bunch of straps/staples/guard strips etc.

 

[hbiss]

New construction, yes. Existing construction it would depend.

-Hal

 

[growler]

Generally I find it much much quicker to drill holes and pull the cable thru them vs dealing with a bunch of straps/staples/guard strips etc.

If you have joist that is possible but what happens when there are roof trusses?

 

[electrofelon]

If you have joist that is possible but what happens when there are roof trusses?

Yes I Agree drilling through trusses is generally not a great idea, people sometimes freak out about that.

 

[Dennis Alwon]

Yes I Agree drilling through trusses is generally not a great idea, people sometimes freak out about that.

It is absolutely a building code violation to drill trusses without an engineer's okay-- perhaps that is why people make a big deal about it. Do not drill a truss.

 

[electrofelon]

It is absolutely a building code violation to drill trusses without an engineer's okay-- perhaps that is why people make a big deal about it. Do not drill a truss.

I am not really disagreeing, just that logically I wonder why why can drill pretty much anything else with just about no rules or oversight whatsoever but drilling a truss is the 8th deadly sin. I did a house that had an engineered framing package and me and the HVAC guy had to drill tons of holes through TJI's, PSLs, and LSL's. He had to drill lots of 6 inch holes for ducting. We had the allowable holes sheet from the manufacturer and it was amazing how much material we we allowed to remove. I guess one argument is that floors are typically designed for sturdiness and "feel" and this puts them very much above the strength they would need to not structurally fail (although in this case, some of the PSL's were supporting walls above them). But then there are rafters and collar ties which again no one blinks and eye at drilling. Perhaps the argument here is that trusses are engineered closer to to design limit where as "rule of thumb framing" is typically way overkill.