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by Smart \$
Replies
5\$\$
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106

Once you go over 30 conductors at a wireway cross...

Once you go over 30 conductors at a wireway cross section, you derate to the table. Bundling and spacing offers no "reprieve" because the wires are inside a raceway.
2. Thread: Single phase from three phase transformer

by Smart \$
Replies
25\$\$
Views
322

Voltage tap conductors usually terminate with...

Voltage tap conductors usually terminate with ring terminals.
3. Thread: Seperate Ground for a Building with Seperate Service

by Smart \$
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7\$\$
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145

Interconnection of grounding electrode systems of...

Interconnection of grounding electrode systems of separate buildings and structures is never required. However, interconnection happens inadvertently through EGC's when the different systems supply...
4. Thread: Single phase from three phase transformer

by Smart \$
Replies
25\$\$
Views
322

Dyn (delta-wye) requires all three conductors...

Dyn (delta-wye) requires all three conductors connected on the primary to get 208V and 120V from the secondary.

If primary has voltage taps, could drop one winding (i.e. disconnect and isolate one...

by Smart \$
Replies
4\$\$
Views
126

Good point to bring up. @Paul There's no gnd...

Good point to bring up.

@Paul
There's no gnd on the the POCO side of the service disconnecting means of grounded systems. Everything is bonded to the grounded [neutral] conductor.

by Smart \$
Replies
3\$\$
Views
92

You can... but you'll have to evaluate a change...

You can... but you'll have to evaluate a change in parameters. Conductors need derated for number in conduit at least to 80%. If 90°C-rated conductors, 350A × 80% puts you at 280A... or 560A for...

by Smart \$
Replies
4\$\$
Views
126

250.24(C)(2) is the correct sizing.

250.24(C)(2) is the correct sizing.

by Smart \$
Replies
2\$\$
Views
172

Perhaps... ...

Perhaps...

http://www.marathonelectric.com/motors/iomManuals.jsp
9. Thread: pvc under a slab

by Smart \$
Replies
17\$\$
Views
484

The NEC does not define underground, but most...

The NEC does not define underground, but most consider anything below the upper surface of an on-grade slab to be underground... and then there's 300.5(B) "Wet Locations. The interior of enclosures...
10. Thread: Max supply side tap

by Smart \$
Replies
4\$\$
Views
118

Can we land...???

Can we land...???
11. Thread: Max supply side tap

by Smart \$
Replies
4\$\$
Views
118

You can line-side connect up to the service...

You can line-side connect up to the service rating... 200A for your example.
12. Thread: Measuring Circumference of a bundle of disimilar cables

by Smart \$
Replies
4\$\$
Views
149

What are the spec' diameters of the conductors? ...

What are the spec' diameters of the conductors?

No easy way to calculate... but drawing up a bundle in CAD and measuring the circ' is pretty straightforward.
13. Thread: pvc under a slab

by Smart \$
Replies
17\$\$
Views
484

A wet location, yes, but not always "outside" the...

A wet location, yes, but not always "outside" the building.

In some instances it is advantageous as "inside" the building... but it does technically have to be within the footprint of the...
14. Thread: PDF Ovelay for Drawings?

by Smart \$
Replies
13\$\$
Views
594

That is typically only true if the print driver...

That is typically only true if the print driver is set for "Print as Image" or some opacity features in the drawing cannot be duplicated by PostScript and must be rasterized.

It is true some...

by Smart \$
Replies
27\$\$
Views
762

There isn't any using 600kcmil, but you can't go...

There isn't any using 600kcmil, but you can't go any smaller in the boxes. You can go smaller in the tray if you make a proper transition. That's all I'm trying to say.

by Smart \$
Replies
27\$\$
Views
762

Yes, but your circuit ampacity still cannot...

Yes, but your circuit ampacity still cannot exceed 110.14(C) limitations, which uses Table 310.15(B)(16) always. If you went with say 5 sets of 500kcmil your circuit ampacity cannot exceed 380A x...

by Smart \$
Replies
27\$\$
Views
762

As the old cliche goes, "back to the drawing...

As the old cliche goes, "back to the drawing board"... :rant:

:D

...but don't forget that your maximum circuit ampacity is per 110.14(C) limitations... and that always use Table...

by Smart \$
Replies
27\$\$
Views
762

Sounds like you are making progress... :thumbsup:...

Sounds like you are making progress... :thumbsup:

Note there is no specific "gap" required, but you will have to keep each set together (conductors immediately adjacent to each other).

MC cable...
19. Thread: PDF Ovelay for Drawings?

by Smart \$
Replies
13\$\$
Views
594

In some cases you can use a print-to-pdf print...

In some cases you can use a print-to-pdf print driver to make a new document without the direct-edit restriction, provided printing is permitted from the original doc'. However, some print-to-pdf...

by Smart \$
Replies
26\$\$
Views
635

They do have that right... ...but even...

They do have that right...

...but even electrical engineer designs cannot supercede Code.

by Smart \$
Replies
27\$\$
Views
762

Simple question... are you using multiconductor...

Simple question... are you using multiconductor or single conductor cable?

I (and the NEC) don't care how you treat the 5 sets of 4#600. What matters for cable tray sizing is whether the...

by Smart \$
Replies
27\$\$
Views
762

Where are you getting these numbers and...

Where are you getting these numbers and equations???

If you are using multiconductor cable, you have to get the diameter from manufacturer's documentation. It'll be one number (diameter) for each...

by Smart \$
Replies
9\$\$
Views
315

I agree. Please make a note of it. :happyyes:

I agree. Please make a note of it. :happyyes:

by Smart \$
Replies
27\$\$
Views
762

Are you certain you are using multiconductor...

Are you certain you are using multiconductor cable? The #1 GND in each cable presents a 250.122(F) grounding issue.

You will have to obtain either diameter or fill data from cable manufacturer's...
25. Thread: Split distribution and 2 disconnects for cleaning?

by Smart \$
Replies
3\$\$
Views
187

The NEC does not cover machine safety switching. ...

The NEC does not cover machine safety switching. I'd look at NFPA 79 and NRTL listing standards (such as UL508) as a first stop.
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