Found this at todays inspection. 200 amp. disconnect with 12ga. wires feeding small double fuse box next to it. This doesn’t seem right to me.
One of the fuses was 30 amp. which I’ve mentioned, but how about the rest?
Where’s the electrical guys??
That’s a double-tap----NO-NO.
Two different sizes of wire (radically) do not seat properly, especially the one on the left. That could begin to arc and get hot…
It needs a fourth wire to the subpanel, probably a ground…
Agreed…and the conduit (if I see it correctly) is probably the grounding.
Definetly wrong!
Was the sub-panel serving an added air conditioner? What does it serve.
That’s the clue. Added by a non-professional.
“Gee, I need to power this thing. Where can I get the juice? Oh, yeah. Just have to tap the main feed.”
Typical.
It is legal to tap a 200a feeder with 12ga wire as long as the tap is in conduit, the O/C device on the load end of the tap will protect the tap and the splicing method is legal.
In this case, if the load in an AC unit you could size the tap to the circuit ampacity on the label and have the tap O/C device sized to the O/C device size on the label.
That could be a 14 on a 30a fuse tapping a 200a feeder the way I read 240.21(B)(1) if that is what the label says.
Short circuit protection, up to 10 feet, is provided by the 200a fuses and overload protection is provided by the motor starter. The 30 (or whatever) is what the manufacturer requires to protect his machine and the branch circuit conductors from short circuits.
The dead rat here is the way he tapped the lug. He could fix it with a couple split bolts.
“He could fix it with a couple split bolts…”
Greg:
Do you recommend that the SB’s be cut into the load side conductors here?
If so, I am not sure that I would ever approve that type of work at all. It was never their intention, the CMP, to allow this type of installation.
http://www.nachi.org/forum/attachment.php?attachmentid=3510&d=1147989801&SSImageQuality=Full
I agree!
I agree they probably needed to make a tap somewhere and thought this looks good as any but we are dealing with a couple of problems.
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This is a double tap and needs to be evaluated.
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If this a 30 amp fuse and 12 gauge wire, that also is a no no.
Russell, if this is an AC unit, 30a on a 12 ga is not unusual or a “no-no”. You follow the label on the unit.
Joe, why is a 240.21 “tap” wrong? It can be protected on the line side by an O/C device up to 10 times the ampacity of the tap. It does not specify that I have to use 240.4(D) to size the downstream O/C device so I could use 440 and 310.16 if this feeds an AC unit (getting a minimum of 14ga). Are you just concerned about using a split bolt on the feeder conductor?
I agree I would have to hold my nose but I also would have a hard time finding the violation if this used a listed splice.
Greg:
The 10 times OC tap rule was not writtten to allow the tap as you describe, and I am not going to give any argument on how some may read it.
On the other hand, how about the 312 wire bending space rules?
I think that would give us enough information so that we can agree.
I don’t want to give anyone any suggestions that seem to “meet the code”
Maybe you should ask the CMP 10 Panel Member over on Chucky Mike’s place
I guess I have just had to deal with what it says and not necessarily what we think they wanted. It is like the guy who puts a Romex out on a stacker, 1.25" to the side of a 3/4" furring strip pinched against a block wall and says he meets 300.4(D) even though we know a guy who misses the stud will hit it with a 1" picture hanger nail.
I can’t go with the code I wish I had, I have to use the one they gave us.
There are other legal splicing methods that do not disturb the bending space of the main conductor if you don’t like split bolts. How about a Kupltap?
You could fault the 14ga assertion but there is still backup since 310.16 says 14ga is good for 20a, 10% of 200. 240.(D), the most stringent standard, backs up the 12ga and that really only affects the B/C O/C device.
BTW I can see why you argue with Jim Pauley 
Greg:
240.21
Read the rule at 4. and see where ALL of the conditions must be applied.
What do you mean with reference to Jim Pauley?
I still don’t see the violation if a listed splicing method was used.
“four” says
The line side fuses were 200a, the tap was 12ga which is good for 20a in virtually any scenario. 10 times the ampacity of the tap is certainly at least 200a. 310.16 says that could be 250a. If I look at 310.16 I could use 14ga with a 40a load side breaker if it was installed as one of the valid exceptions to 240.4(D), like a <1hp> motor or HVAC. The “ampacity” of 14ga is 20a per 310.16. It is only 240.4(D) that makes us “protect” it with a 15a breaker.
I am not saying this is a prudent design decision or what I would like to see the installer do but I am having a hard time finding a violation.
My reference to Jim Pauley is that he likes to point out these things that look bad but are following the letter of the code. Taps and motors are two places that really can make you go hmmm when you look at the worst case scenarios.
I believe the Home Inspector wolud stay on solid ground if the report recommended the following:
When this safety switch was first installed it was designed to include a "Line and a Load."
ok… I would call it out simply because of the fact the termination point is not designed for this method of “TAP”
I will say most refer to this aticle when tapping service feeders…and mainly that.
I say Jae and Larry made the right call