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Home > Archive > Electrical Engineering > February 2008 > Bending radius in a gutter.
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Bending radius in a gutter.
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| Long Ranger 2008-02-11, 3:25 am |
| For years I have used a chunk of gutter as a substitute for an LB. Lately
the inspection Nazis around my area have taken to dissallowing the practice,
and cite bending radius as a reason. I maintain that a gutter is covered by
section 374, and pertains more to a wireway than a junction box. Note that
bending radius and multiples of pipe diameters are not mentioned there.
Besides, the typical gutter I install allows more cross sectional area and
bending radius than a "legal" LB. I'd like some opinions, if you will.
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| Gerald Newton 2008-02-11, 3:25 am |
| On Feb 10, 9:09=A0pm, "Long Ranger" <lorpkins@earthlink .net> wrote:
> For years I have used a chunk of gutter as a substitute for an LB. Lately
> the inspection Nazis around my area have taken to dissallowing the practic=
e,
> and cite bending radius as a reason. I maintain that a gutter is covered b=
y
> section 374, and pertains more to a wireway than a junction box. Note that=
> bending radius and multiples of pipe diameters are not mentioned there.
> Besides, the typical gutter I install allows more cross sectional area and=
> bending radius than a "legal" LB. =A0I'd like some opinions, if you will.
This was a change in the 2005 NEC and basically requires that the
distance between raceway
entries where you turn a 90 degrees in your conductors No. 4 or larger
have a distance between the raceways
of 6 times the larger of the two raceways.
I have an illustration at slide 133 at:
http://electrician2.com/2005nec1/20...iles/frame2.htm
366.58 Insulated Conductors.
(A) Deflected Insulated Conductors. Where insulated
conductors are deflected within an auxiliary gutter, either at
the ends or where conduits, fittings, or other raceways or
cables enter or leave the gutter, or where the direction of
the gutter is deflected greater than 30 degrees, dimensions
corresponding to one wire per terminal in Table 312.6(A)
shall apply.
(B) Auxiliary Gutters Used as Pullboxes. Where insulated
conductors 4 AWG or larger are pulled through an
auxiliary gutter, the distance between raceway and cable
entries enclosing the same conductor shall not be less than
that required in 314.28(A)(1) for straight pulls and
314.28(A)(2) for angle pulls.
| |
| Long Ranger 2008-02-11, 3:25 am |
|
"Gerald Newton" <electrician@electrician2.com> wrote in message
news:9227eb00-7c6f-47a8-928b-81cddb12bbb3@y5g2000hsf.googlegroups.com...
On Feb 10, 9:09 pm, "Long Ranger" <lorpkins@earthlink .net> wrote:
> For years I have used a chunk of gutter as a substitute for an LB. Lately
> the inspection Nazis around my area have taken to dissallowing the
> practice,
> and cite bending radius as a reason. I maintain that a gutter is covered
> by
> section 374, and pertains more to a wireway than a junction box. Note that
> bending radius and multiples of pipe diameters are not mentioned there.
> Besides, the typical gutter I install allows more cross sectional area and
> bending radius than a "legal" LB. I'd like some opinions, if you will.
This was a change in the 2005 NEC and basically requires that the
distance between raceway
entries where you turn a 90 degrees in your conductors No. 4 or larger
have a distance between the raceways
of 6 times the larger of the two raceways.
I have an illustration at slide 133 at:
http://electrician2.com/2005nec1/20...iles/frame2.htm
366.58 Insulated Conductors.
(A) Deflected Insulated Conductors. Where insulated
conductors are deflected within an auxiliary gutter, either at
the ends or where conduits, fittings, or other raceways or
cables enter or leave the gutter, or where the direction of
the gutter is deflected greater than 30 degrees, dimensions
corresponding to one wire per terminal in Table 312.6(A)
shall apply.
(B) Auxiliary Gutters Used as Pullboxes. Where insulated
conductors 4 AWG or larger are pulled through an
auxiliary gutter, the distance between raceway and cable
entries enclosing the same conductor shall not be less than
that required in 314.28(A)(1) for straight pulls and
314.28(A)(2) for angle pulls.
So if that is such a concern, why haven't LBs been subjected to the same
rule?
| |
| Gerald Newton 2008-02-11, 3:25 am |
| On Feb 10, 10:10=A0pm, "Long Ranger" <lorpkins@earthlink .net> wrote:
> "Gerald Newton" <electric...@electrician2.com> wrote in message
>
> news:9227eb00-7c6f-47a8-928b-81cddb12bbb3@y5g2000hsf.googlegroups.com...
> On Feb 10, 9:09 pm, "Long Ranger" <lorpkins@earthlink .net> wrote:
>
y[color=darkred]
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at[color=darkred]
nd[color=darkred]
>
> This was a change in the 2005 NEC and basically requires that the
> distance between raceway
> entries where you turn a 90 degrees in your conductors No. 4 or larger
> have a distance between the raceways
> of 6 times the larger of the two raceways.
> I have an illustration at slide 133 at:http://electrician2.com/2005nec1/20=
05_nec_files/frame2.htm
>
> 366.58 Insulated Conductors.
> (A) Deflected Insulated Conductors. Where insulated
> conductors are deflected within an auxiliary gutter, either at
> the ends or where conduits, fittings, or other raceways or
> cables enter or leave the gutter, or where the direction of
> the gutter is deflected greater than 30 degrees, dimensions
> corresponding to one wire per terminal in Table 312.6(A)
> shall apply.
> (B) Auxiliary Gutters Used as Pullboxes. Where insulated
> conductors 4 AWG or larger are pulled through an
> auxiliary gutter, the distance between raceway and cable
> entries enclosing the same conductor shall not be less than
> that required in 314.28(A)(1) for straight pulls and
> 314.28(A)(2) for angle pulls.
>
> So if that is such a concern, why haven't LBs been subjected to the same
> rule?
Good question. I do not know the answer but I guess the LBs are
specifically listed for the application while gutters are field
modified to perform a similar function.
To make sure the field modifications are acceptable the Code has
adopted these new rules for gutters that were in other parts of the
code for pull boxes.
The dimensions given in (B) are only applicable to gutters used as
pullboxes. That gives you some slack if you can convince the
inspector that you are not using the gutter as a pull box.
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