2 Electrical Questions: Loops in Service Panel, Slack at Boxes

Folks:

More a style question than a code question.

Do you feel it is preferable to pull the service conductors into the panel and run them right to the lugs, or cut them long and form them into a loop?

The loops add a little more flexibility, and give you some extra wire if somewhere down the road the end should corrode or burn, but at the same time, they take up a lot of space in the box, especially if you're using larger gauges.

What does everybody think?

Another question: when trimming boxes, I tend to measure 8" or so along the cable jacket, then staple it at that point on the cable, but closer to the box, leaving a standing loop. I feel this helps relieve potential strains, and allows the cable to be pulled into the box at some future time if more wire is needed, or the box needs to be moved slightly. Does anybody else do this? What do you think of this practice?

Cordially yours: A P

Reply to
autobus_prime
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I try to always leave a little slack in anything new I install after a lifetime of wishing others had left me a little extra..........

might look a little messy but when you need a extra inch.

i try to stuff the lack back up in walls whenever possible

Reply to
hallerb

I like the loops, but sometimes the larger wires are difficult to curl. They are also good for expansion and contraction so there is no strain on the lugs.

I tend to leave some slack along the line in case the customer decides to move an outlet or switch unfortunately the price of copper keeps me from leaving big loops, but I have heard of one contractor in my area that does it.

Reply to
John Grabowski

In virtually all of the work I have seen (done well) in a service panel, the conductors run straight down the sides (parallel to the vertical side of the panel) then make a tight 90-degree "turn" into the breaker lug. I have never seen a telco-like "slack loop" where the conductor extends PAST the lug then makes a 180-degree turn back up - then a 90 into the lug. To me, that would be overkill.

In any ostensibly permanent installation there should be enough slack to remake the connection at least once, perhaps twice. Any more slack wire than that is wasted, would tend to crowd the enclosure and possibly become a rats' nest if future work is performed in the box.

You leave a slack "loop" OUTSIDE the box? If yes, I disagree with the practice. The romex should proceed straight and true into the box and, per code, be secured outside the box and, where it enters the box, with a proper clamp. All slack wire should be contained INSIDE the box. There should be enough slack wire so that the wiring device extends COMPLETELY outside the box to facilitate making its connections.

I don't.

Not much.

Leaving slack cable inside a wall is a bad idea for several reasons: The slack will interfere with insulation. It may be vulnerable to damage by future attachments to the wall. It is also contrary to common installation practice.

Accommodating for the POSSIBILITY of moving the box in the future SOUNDS good but is impractical. I can't remember ever moving a box JUST ENOUGH so that the slack you imply would accommodate the move. I have always had to replace the run or splice on a new section inside the old box (blank cover plate or just another duplex receptacle) and place the NEW box where needed.

Reply to
Jim Redelfs

I don't leave loops in panels because there is a 40 per cent fill limit in the side gutter spaces. If there is a need for extending the conductors in the future which generally is very unlikely, crimp splices can be applied to pig tails. For boxes, the rule is 6 inches of free conductor is required measured from where the conductor enters the box. Again, leaving excess slack in the box can be a problem since there are code rules on box fill. As a matter of fact there is a specific rule on slack introduced in the 2005 NEC that requires that if the looped conductor is not less than twice the free length required in 300.14 it counts as two conductors when determining box fill. REF: cited below:

2005 NEC 314.16 (B) Box Fill Calculations. The volumes in paragraphs 314.16(B)(1) through (B)(5), as applicable, shall be added together. No allowance shall be required for small fittings such as locknuts and bushings. (1) Conductor Fill. Each conductor that originates outside the box and terminates or is spliced within the box shall be counted once, and each conductor that passes through the box without splice or termination shall be counted once. A looped, unbroken conductor not less than twice the minimum length required for free conductors in 300.14 shall be counted twice. The conductor fill shall be calculated using Table 314.16(B). A conductor, no part of which leaves the box, shall not be counted. Exception: An equipment grounding conductor or conductors or not over four fixture wires smaller than 14 AWG, or both, shall be permitted to be omitted from the calculations where they enter a box from a domed luminaire (fixture) or similar canopy and terminate within that box.
Reply to
Jerry

JR:

I'm thinking mostly about exposed work here, although I also leave this extra when doing new work in a wall. Old work in a wall is always going to have slack.

Jerry - That provision only applies to conductors passing through without splicing, as in "courtesy loops" left for the next guy. If you strip and cut the wire off 14" long and skin it at the midpoint and end for attaching to 2 device screws, it wouldn't count as two.

A P

Reply to
autobus_prime

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