Tap rule clarification needed

[Tainted]

See sketch below showing 4 disconnect switches and a wireway.

Sketch shows wire A, B, and C
Sketch also shows tap X, Y, and Z

I understand code says you cannot tap a tap conductor. If you do a tap at tap X, is wire B and wire C considered a tap conductor and therefore taps Y and Z are illegal taps?

To make it legal, would taps Y and Z need to be relocated to tap X?

 

[augie47]

As long as wire "A" is full size based on your supply OCP, taps X,Y, & Z can be done as shown assuming they meet the 240.21 rules.

 

[Tainted]

As long as wire "A" is full size based on your supply OCP, taps X,Y, & Z can be done as shown assuming they meet the 240.21 rules.

To me I thought the rule meant that if you have tap X, then it makes wire B and C a "tap conductor" therefore you cannot tap it. And that all taps must go to tap X for it to be legal

 

[wwhitney]

A wire segment is a tap conductor if the upstream OCPD does not comply with 240.4, and the wire segment relies on a downstream OCPD to comply with 240.4. 240.21 then gives you the limitations on that wire segment.

So as long as segments A, B, and C are "full sized" (not taps), then X, Y, and Z are just 3 different taps to the same feeder.

Cheers, Wayne

 

[Tulsa Electrician]

If you splice A to B and tap( x ).
A and B same size and meets 240 as mentioned x is you tap conductor.
How you splice it it up to you.
If A was one long wire and you use a split bolt sized for run (A) and tap( x) then use another split bolt and tap to A and then tap (z) to A.

Your taps are x,y and z.

Another way to look at is if you had a branch circuit lighting fixture( luminary)tap in house or commerical building.
#12 in to box #12 out of box and a fixture tap to the light. The smaller conductor to the light is you tap. The #12 is spliced to the tap conductor. However different tap rules. Same principle.

 

[jim dungar]

Don't use industry slang where a connection of three wires is a tap when using the rules in article 240. You must use the NEC definition of a tap.

If your wires B, and C are all adequately protected by the device ahead of wire A , the NEC does not consider them as taps.

 

[jaggedben]

In my opinion segment 'C' doesn't need to be full size, it's just an extension of tap Z.

The 'you cannot tap a tap rule' isn't really explicit. It's mostly implied.

 

[don_resqcapt19]

In my opinion segment 'C' doesn't need to be full size, it's just an extension of tap Z.

The 'you cannot tap a tap rule' isn't really explicit. It's mostly implied.

While the code rule does not use the word tap, it is pretty clear and not just implied.

240.21 ,,,Conductors supplied under 240.21(A) through (H) shall not supply another conductor except through an overcurrent protective device meeting the requirements of 240.4.

 

[petersonra]

In my opinion segment 'C' doesn't need to be full size, it's just an extension of tap Z.

The 'you cannot tap a tap rule' isn't really explicit. It's mostly implied.

The code is pretty clear about such things. It doesn't say you can't tap a tap but it does say a tap has to end at an over current protection device. That makes it pretty obvious.

 

[jaggedben]

While the code rule does not use the word tap, it is pretty clear and not just implied.

Right so if I splice two sections of tap conductor together is that a violation? (Where else would the code treat that as more than one conductor?) Does it matter if they are the same size or not, as long as they both meet the ampacity requirements?

I'll reword: 'You can't tap a tap' is an imprecise and colloquial phrasing and depending exactly what you think it means it may not mean what the code actually says. Most notably with respect to the OP, the code does not say you can't branch multiple 'taps' (non-code-definition meaning) off a feeder in various directions.