Lashing or rope bracing of phase conductors in CT Cabinet

[StevenLeuck]

I've been researching this subject since yesterday without receiving any definitive reply so was hoping someone here in the Forums might be able to shed some light on this subject......
Early this week, out of the blue, we had a local book-learned electrical inspector (was never an electrician) turn down a service inspection because he wanted the phase conductors lashed together on both the line and load sides of the service conductors inside a 400A rated CT Cabinet. In my 43 years of managing electrical construction (after a short apprenticeship career) I have never had this requirement put on us. He claimed it was because the equipment (BLine 6067-HAL CT Mounting bus) had a sticker on it depicting the lashing and that since the manufacturer showed it, it MUST therefore be a requirement for a code-approved installation of the equipment in question. We asked for an NEC reference but he couldn't give one.
I searched the Forum for this subject but found only one ten year old thread. Among the responses was one from IWire who stated, without reference, that it depends on the rated fault current. Unfortunately I haven't been able to find any reference to this online.
I then contacted the Cooper/BLine metering people directly. They pointed me to UL 414 and a couple of specific articles in it. Unfortunately,unless you're willing to shell out $1,000 for a download of a UL Chapter, you can't get to it to even read it.
So,.... the bottom line is that we don't think the inspector is correct in assuming that since there's a sticker on the equipment that the lashing of conductors is required unless there is a specific need (eg, fault current threshold of some sort) to do it and that diagram on the sticker is only there for reference if needed. Has anyone out here had experience with this and/or has a specific reference to what that threshold might be, if there is one? I can't find anything in the NEC about it and none of my guys are familiar with it either.
Looking/hoping for some collective assistance here.
Thanks!
PS, the attachment is a simile of the sticker that is on the equipment that BLine emailed me

 

[jim dungar]

Lashing is a common requirement when available fault currents exceed 65kA. I believe every major electrical equipment manufacturer include this in their instructions.

According to your post, lashing is only required if the CT cabinet does not have an SCCR on its label..

 

[Open Neutral]

Looking at CT cabinet for a 200,000A installation.
It's well lashed.
What bothers me is why isn't the cabling in the adjacent main disconnect also wrapped?
CT
Main

 

[electrofelon]

What a coincidence, I just installed a 6067 HAL today and noticed the lashing label. I will perform the lashing. I think the inspector is well within his rights to enforce that based on 110.3(B). I have noticed the lashing requirement in CT cans before but not in any other gear, could be I just didn't read the destructions

 

[paulengr]

What I commonly see for “CT lashing” is tie wraps woven in an “X” pattern to center the cables in the window of the CT.

Haven’t seen a lot of phase lashing. I suppose where the wiring is secured by lugs such as disconnects it wouldn’t be necessary.

 

[tom baker]

With respect...inspector was correct. Lashing is required, and is very important. For the ones I have lashed, the instructions are very specific as to the type of rope, knot type and numer. I felt like a bosoms mate when I did the lashing.

 

[jim dungar]

Haven’t seen a lot of phase lashing. I suppose where the wiring is secured by lugs such as disconnects it wouldn’t be necessary.

Actually, proper lashing is required to handle the short circuit magnetic forces that want to move the conductors and pull them loose from the terminals.

 

[StevenLeuck]

With respect...inspector was correct. Lashing is required, and is very important. For the ones I have lashed, the instructions are very specific as to the type of rope, knot type and numer. I felt like a bosoms mate when I did the lashing.

This is what we're finding out now too after diving into this.... what we've also found out is that of the 30 or so municipalities we commonly deal with here, only one has required it... this being our first time with it.

 

[StevenLeuck]

Today I received the below follow up from BLine. Interesting... some have mentioned a 65kaic threshold but this guy mentions 10k here:

"It is required for units from 10KAIC to the marked rating on the device. UL 414 pulls from UL 891 (switchboards) on bracing requirements for CT structures. To your point, AHJ’s have not been enforcing it, but in this new culture of electrical safety, more and more are now advocating it. It is a good practice to do, regardless."

 

[jim dungar]

Technically the terminology would be SCCR (short circuit rating) or SCA (short circuit, available). AIC should only be used with protective devices that interrupt fault currents, like breakers and fuses.

I don't know about CT cabinets like you have, but I have never seen lashing for switchboards under 65kSCCR, which may be because of the way UL tests them.

 

[tom baker]

The MCCs I have installed, when there is a service disconnect, has a requirement for supporting conductors on the line side of the disconnect, seems like its a piece of hardwood that is lashed across the conductors.

 

[Open Neutral]

I recall images in Machines 430 class.

One was the new trench in a shop's concrete floor, cable in place and wet cement poured. There was a minor oops {aka dead short} at the new panel. When the panel was lit, the cables flew out of the trench and danced, spraying drying concrete everywhere. No one killed but a nearby worker was knocked sidewise and had broken ribs.

I always think of that image when I close a bigger than 20A breaker.

 

[PaulMmn]

I recall images in Machines 430 class.

One was the new trench in a shop's concrete floor, cable in place and wet cement poured. There was a minor oops {aka dead short} at the new panel. When the panel was lit, the cables flew out of the trench and danced, spraying drying concrete everywhere. No one killed but a nearby worker was knocked sidewise and had broken ribs.

I always think of that image when I close a bigger than 20A breaker.

It's good to have an image of something that went wrong, but not as wrong as it could have been! Too bad they can't be installed in every new apprentice!

 

[jaggedben]

With respect...inspector was correct. Lashing is required, and is very important. For the ones I have lashed, the instructions are very specific as to the type of rope, knot type and numer. I felt like a bosoms mate when I did the lashing.

Bosun's mate? (Or boatswain's mate?)

 

[Cow]

We've been lashing for years. But only the conductors we install. We use those same B Line CT cans too.

Pacific Power installs their conductors to the line side of the CT can, we don't lash their wiring. But for all the other power companies that have us bring the line side wiring into the CT can, we lash both sides, of course.

 

[ron]

This video is about lashing correctly on tray but it is the same concept

 

[Open Neutral]

It's good to have an image of something that went wrong, but not as wrong as it could have been! Too bad they can't be installed in every new apprentice!

The other one was the generator being brought on line in parallel, but not when the three sync lights were off, but on. {oops}

So the armature tried to instantaneously rotate to be in the right place, and could not. So the stator moved instead; snapping off the mounting feet, rolling the M-G across the floor, blasting through the wall and across several cars in the parking lot.

(There were several reasons a heavy industry job never appealed to me.....)

 

[ggunn]

I felt like a bosoms mate when I did the lashing.

Some typos are just plain funny.