Panduit Wire Jumper Clarification

I can't remember where I heard that if a block of fuses/terminal blocks that are all the same node (Voltage, Neutral, Common, or Ground) the jumper wires does not need to go back in and out of the panduit. Does anybody remember the NEC standard number?

RRoc said:

I can't remember where I heard that if a block of fuses/terminal blocks that are all the same node (Voltage, Neutral, Common, or Ground) the jumper wires does not need to go back in and out of the panduit. Does anybody remember the NEC standard number?

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I've been designing panels for years and have never heard of that NEC requirement. As a solution that would avoid any NEC conflict, why not use the Panduit jumpers that are designed for the terminals or fuse blocks? In the end I believe they would work out better for you.

the manufacturer terminal jumpers are so much nicer to use and easier to use and look really clean too.

the only ones I have never been a fan of are the ones of certain fused blocks that you need to notch out the terminal and screw it underneath, makes it real confusing on how jumpering is done for someone who has never seen them.

I have heard of specific engineering firms with jumper wire requirements but nothing code relate, mind you I deal with CSA

My I/O is designed fuse block then terminal block. Grouping of fuses can't be done so a comb won't work for this application. We do this to prevent the I/O wires from being split. Grouping blocks have been an issue because electricians and operators have to get the i/o power block up high on the din rail and the i/o block way down the din rail.

i'm not perfectly clear on what you are trying to accomplish, but
you need to aware of nfpa 79, nec 70, and nfpa70e - arc flash.

arc flash rules are becoming more previlent these days and you need to look a
the requirements.

separate the main disconnect, 480 volt power, 240 volt power, 120 power, and dc. use finger safe terminals or have a lexan protective cover over exposed terminals.

Arc flash is a hot topic here along with loto!

regards,
james

RRoc said:

My I/O is designed fuse block then terminal block. Grouping of fuses can't be done so a comb won't work for this application. We do this to prevent the I/O wires from being split. Grouping blocks have been an issue because electricians and operators have to get the i/o power block up high on the din rail and the i/o block way down the din rail.

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been there I got into the habit of sizing my blocks to make sure I could still use the combs and just bust every second tooth out, but I know you don't always have freedom to pick your blocks

Hopefully this clears it up. You can group like blocks together fuses and terminals and use a comb instead of a wire jumper. Other applications designers layout out the a fuse block on top of a terminal block to meet client/operator needs. Combing is not a option no more, you have to use a jumper wire or bust out a teeth on a comb if feasible to pass the voltage/neutral.

My original questions was that is there any rule that a jumper wire has to go back into the panduit and come back out if multiple jumpers are required or can we just make short jumper wires and be done with it. From the threads i'm seeing there is no letter of the law.

Not sure why Arc Flash came up. This is more for I/O module wiring practices.

there are no jumper length requirements in the NEC that I'm aware of, and I've seen all lengths in the field.

This is more along the lines of good practice, not requirements, but I prefer all wire jumpers to go in/out of the panduit. IMO, it just looks better.

Thanks Scott. I on the other prefer the other way around. If the jumper wire is daisy chained down (not going in/out of the panduit) you don't need to wire tags each wire, just the homerun wire.

RRoc said:

Thanks Scott. I on the other prefer the other way around. If the jumper wire is daisy chained down (not going in/out of the panduit) you don't need to wire tags each wire, just the homerun wire.

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I find it makes more clear to anyone looking in the panel what is going on as well

It's mostly aesthetics. And is situational and subjective one which way looks better. Two terminals, close together, no wires crossing the jumper, a short jumper close to the device may be better. But if the distance is larger, and other wires may cross over to other devices or terminals on the device in between the jumped locations, going up to the wire duct and then back out may look better. Wire crossings and such being hidden by the duct covers make the panel look cleaner.

I don't think the code has much of anything in terms of how something looks. (Other than that "workmanlike manner" phrase).