Using a Minnie strap/ Conduit Clips as addiquate raceway

[iwire]

Re: Using a Minnie strap/ Conduit Clips as addiquate raceway

In general die cast fittings are nowhere near the strength of steel fittings in either set screw or compression.

A steel coupling will on it's own support another 10' of conduit until you get the support on the new section.

A die cast fitting will usually split open if used like that.

[ September 17, 2005, 12:25 PM: Message edited by: iwire ]

 

[sandsnow]

Re: Using a Minnie strap/ Conduit Clips as addiquate raceway

Originally posted by geezer:

Larry, Do you require a grounding conductor in the conduit for these types of installations? It would seem to be a reasonable requirement, though probably not needed IF the installation is RMC with properly tightened couplings.

Nope.

 

[infinity]

Re: Using a Minnie strap/ Conduit Clips as addiquate raceway

As an electrician, if you had a choice and cost were no object, what type of EMT fitting would you use? We prefer steel set screw but it seems like engineers love to spec compression fittings which IMO really stink.

[ September 17, 2005, 02:44 PM: Message edited by: infinity ]

 

[iwire]

Re: Using a Minnie strap/ Conduit Clips as addiquate raceway

Originally posted by infinity:
As an electrician, if you had a choice and cost were no object, what type of EMT fitting would you use? We prefer steel set screw but it seems like engineers love to spec compression fittings which IMO really stink.

My choice would be steel set screw fittings.

90% of the time when I do get steel compression they are imported junk with poor tolerances that can not be tightened.

Occasionally we get really nice steel compression fittings that work very well.

OZ-Gedney with deep throats are very nice, I imagine they are not very economical.

 

[cselectric]

Re: Using a Minnie strap/ Conduit Clips as addiquate raceway

Originally posted by infinity:
As an electrician, if you had a choice and cost were no object, what type of EMT fitting would you use? We prefer steel set screw but it seems like engineers love to spec compression fittings which IMO really stink.

Given the option (with money as no object) I'd take all steel set screws. I actually quite like steel compression fittings, but I've seen too many electricians that refuse to carry a second pair of channellocks to trust they'll be installed correctly.

 

[copper123]

Re: Using a Minnie strap/ Conduit Clips as addiquate raceway

I have heard this around dif jobs many times, maybe its just an urban myth: After the last big Cal. earthquake they took a look at how the dif. conduit systems held up. The S.S. fittings held much better than the Comp. fittings. I have always heard that one of the main reason that on expensive jobs they spec comp is the ability to resist pulling apart. Personally, I have just the opposite view. They seem to come apart easier and make a less than perfect bonding method. However, maybe half of that is just as the fellow above described - improper installation methods for comp fittings

 

[jimwalker]

Re: Using a Minnie strap/ Conduit Clips as addiquate raceway

I am curious as to why a grounding conductor is not required.We always run a ground to anything we pull.Do many of you trust emt and couplings ? Chances of emt getting loose in long runs is too high and if supported by alltread its even worse.
As to fastening his emt i would use grid wire and attach both ends then batwing it.

 

[sandsnow]

Re: Using a Minnie strap/ Conduit Clips as addiquate raceway

Originally posted by jimwalker:
I am curious as to why a grounding conductor is not required.

250.118(4) says you don't have to.
I have seen many ceiling spaces during TI of long existing installations where couplings are bent, broke or pulled apart and there is no EGC for the circuit.
Many times it is the demo contractors who leave such lovely parting gifts.
And the lucky winner is the owner who gets a corrx to have it fixed.
If someone proposed an amendment to req EGC in metal raceway I think the steel tube institute would fight it tooth and nail.

I heard AZ has a state ordinance that req's EGC in EMT or maybe all metal raceways.

 

[iwire]

Re: Using a Minnie strap/ Conduit Clips as addiquate raceway

Originally posted by sandsnow:
Many times it is the demo contractors who leave such lovely parting gifts.

It's much the same here, the demo guys are great at what they do. :roll:

 

[cselectric]

Re: Using a Minnie strap/ Conduit Clips as addiquate raceway

Originally posted by iwire:

Originally posted by sandsnow:
Many times it is the demo contractors who leave such lovely parting gifts.

It's much the same here, the demo guys are great at what they do. :roll:

Don't even get me started on the demo crews. I spent half a day Friday replacing a pipe run (containing the power circuit for a fire alarm system) that the Demo guys ripped out... after I spray painted it orange, showed it to them and told them that they were not to touch it under any circumstances. I figured even a knuckle dragging "manual demolition technician" would understand, and be able to see, orange paint.

 

[iwire]

Re: Using a Minnie strap/ Conduit Clips as addiquate raceway

Originally posted by cselectric:
I figured even a knuckle dragging "manual demolition technician" would understand, and be able to see, orange paint.

You would think so

The last good size 'make safe' I did I had 5 guys to the Demo guys 20 or 25, I had to just give up and shutdown the feeders to the entire floor (about 30,000 sq ft) until they finished.

The fire alarm we spliced out at the core until the end of the day then patched in what we had to.

Bob

[ September 17, 2005, 07:09 PM: Message edited by: iwire ]

 

[cselectric]

Re: Using a Minnie strap/ Conduit Clips as addiquate raceway

I fully understand giving up when faced with a demo crew. I used to walk through a job and try to find pipe runs that could be reused. It isn't worth the effort of finding them and marking them, the Demo crews inevitably destroy them.

This make safe was quite annoying. I cut everything loose from the panels (even removed the first 10' of pipe myself, so they would know it was dead.) I then spray painted the one pipe that I could not make safe (this is a strip mall, the F/A feed is off of the house panel and passes through the space I am working on.) They ripped out the orange painted pipe, and then complained that it was hot. "We thought you said everything was safe, and my guy burned up his pliers on that pipe." I almost smacked the guy.

 

[iwire]

Re: Using a Minnie strap/ Conduit Clips as addiquate raceway

Originally posted by cselectric:
I then spray painted the one pipe that I could not make safe (this is a strip mall, the F/A feed is off of the house panel and passes through the space I am working on.)

I am with you there.

The company I work for remodels very large retail occupancies. We spent about a year remodeling this place.

The way it would work is the carpenters would box a large area of the store off from floor to the deck, then that day while the store was open the demo guys would 'clean out that box'. We owned all repairs to keep the store operation.

HVAC controls, cash registers, fire alarms what ever broke we had to fix.

Don't let the data guys fool you, one data home run can run two registers and you can spice cat 5 with wire nuts.

Don't everyone jump on me, it was all replaced eventually.

 

[geezer]

Re: Using a Minnie strap/ Conduit Clips as addiquate raceway

An inspector can not require it, as the NEC does not require it.

Looking at 250.4, General Requirements for Grounding and Bonding, It might be argued that for the type of installation originally discussed in this post that the AHJ may very well require that the grounding conductor be included in the conduit.

In my opinion, the following references to the 2002 NEC would support the authority of an inspector to require an EGC to assure a permanent and effective ground-fault path.

80.13 lead paragraph and (1)
90.4
250.4 lead paragraph and (A)(1)&(5)
250.118 lead paragraph

[ September 17, 2005, 10:54 PM: Message edited by: geezer ]

 

[copper123]

Re: Using a Minnie strap/ Conduit Clips as addiquate raceway

we did a supermarket store remodel one summer. They wanted to keep the store open while the remodel was going on. This was crazy in the first place. Anyhow, on July 3rd, the carpenters were doing demo work on a main wall. We didn't know it at the time, but all the data UTP that fed into the walker duct was in that wall in a 2" conduit. Just like all the post from above, those fellas didn't give a rip, the took a sawzall and cut through all of it. Wammo, every register from a bank of about 14 went down for the count. The store was packed full of folks with watermelon, hamburgers, all the stuff for the 4th. It was a huge thing. I was not running the job, but the company I worked for had a great policy. At the Pre Con meeting they had a document that was read and signed that cautioned about doing demo work in the building. If any conduit had to be cut it had to be painted and verified by a electrician and on most all cases, taken out by the same. It certainly was a get out of jail free card. Right after they got the data lines going again, a ceiling guy went screaming across the floor with a man lift and broke off a 1" sprink. They had water running out the door by the time it was shut down.

 

[iwire]

Re: Using a Minnie strap/ Conduit Clips as addiquate raceway

Sounds like what I see around here now too, major renovation while open. Eventually an accident will happen and customers will be hurt.

Someone had a brilliant plan doing demo the day before a Holiday. :roll:

I was sent to work on dairy cases at a large supermarket the day before thanksgiving. To crowded to move. :roll:

 

[infinity]

Re: Using a Minnie strap/ Conduit Clips as addiquate raceway

I have heard this around dif jobs many times, maybe its just an urban myth: After the last big Cal. earthquake they took a look at how the dif. conduit systems held up. The S.S. fittings held much better than the Comp. fittings.

This isn't an urban legend. There was an article in a trade magazine years ago, I'll guess EC&M, that stated that following a big earthquake in California the only fittings that were still together were steel set screw. The die cast ones broke apart and the compression type pulled apart. But still today engineers love to spec the stupid compression type.

It's always fun to have a rack of large conduit and try to tighten a compression fitting with a pair of 18" chain wrenches when the pipes are spaced an inch apart.

 

[cselectric]

Re: Using a Minnie strap/ Conduit Clips as addiquate raceway

My favorite is "midnight remodels" done on Restaurants. Start at 11PM, drive up doesn't close until 1AM, can't get into the kitchen until 1:30AM. Whatever section you are working on has to be 100% finished, working and cleaned to health department standards by 8AM.

The only thing better than that is the one customer I have that insists we do all work during normal business hours. Nothing like doing lighting service on 18' lids during business hours. It's a lovely mix of platform lift, overhead work, curious customer, fragile store stock and narrow isles.

 

[iwire]

Re: Using a Minnie strap/ Conduit Clips as addiquate raceway

Originally posted by geezer:

An inspector can not require it, as the NEC does not require it.

Looking at 250.4, General Requirements for Grounding and Bonding, It might be argued that for the type of installation originally discussed in this post that the AHJ may very well require that the grounding conductor be included in the conduit.

In my opinion, the following references to the 2002 NEC would support the authority of an inspector to require an EGC to assure a permanent and effective ground-fault path.

80.13 lead paragraph and (1)
90.4
250.4 lead paragraph and (A)(1)&(5)
250.118 lead paragraph

You sure do know how to get my attention.

1) 80.13 lead paragraph and (1)

Article 80 is not code it is informational only. I do not know anyplace that specifically adopted it.

80.5 Adoption.
Article 80 shall not apply unless specifically adopted by the local jurisdiction adopting the National Electrical Code.

2) 90.4

90.4 does not allow an inspector to require items not required by the NEC.

3) 250.4 lead paragraph and (A)(1)&(5)

250.4 General Requirements for Grounding and Bonding.
The following general requirements identify what grounding and bonding of electrical systems are required to accomplish. The prescriptive methods contained in Article 250 shall be followed to comply with the performance requirements of this section.

That says follow 250, it does not say follow 250 and whatever the inspector wants.

250.4(1) & (5) are simple statements of what the grounding is supposed to accomplish.

Considering that when the inspector is looking at this pipe run in question 250.4(1) & (5) will be satisfied the inspector can not fail the job for what may happen in the future.

4) 250.118 lead paragraph

That paragraph does not require both.

250.118 Types of Equipment Grounding Conductors.
The equipment grounding conductor run with or enclosing the circuit conductors shall be one or more or a combination of the following:

All that paragraph is saying is I am allowed to use both, never required.

Considering the raceway in question if you where inspecting it and did not like it in my opinion your best option would be to write it up for 300.11

300.11 Securing and Supporting.
(A) Secured in Place. Raceways, cable assemblies, boxes, cabinets, and fittings shall be securely fastened in place......

That sounds very open to interpretation by the inspector. In other words I could not fight it.

Bob

[ September 18, 2005, 06:39 AM: Message edited by: iwire ]

 

[geezer]

Re: Using a Minnie strap/ Conduit Clips as addiquate raceway

1)

Article 80 is not code it is informational only. I do not know anyplace that specifically adopted it.

Are you saying that because you know of none there are none?

2)

90.4 does not allow an inspector to require items not required by the NEC.

90.4 does allow an inspector to interpret rules and decide on the approval of equipment and materials.

3)

The prescriptive methods contained in Article 250 shall be followed to comply with the performance requirements of this section.

That says follow 250, it does not say follow 250 and whatever the inspector wants.

250.4(1) & (5) are simple statements of what the grounding is supposed to accomplish.

Considering that when the inspector is looking at this pipe run in question 250.4(1) & (5) will be satisfied the inspector can not fail the job for what may happen in the future.

You may be confusing "whatever the inspector wants" for the inspectors interpretation of what the code requires. The inspector may look at "250.118... shall be one or more or a combination of the following", and interpret the "or more, or a combination of the following" along with, "in a manner that establishes an effective ground fault current path" from 250.4(A)(4), and "shall be installed in a manner that creates a permanent, low-impedance circuit..." from 250.4 (A)(5), to mean that for the particular type of installation discussed in this post that a EGC must be included in the EMT. The inspector may simply be attempting to assure that the installation complies with the"performance requirements of this section"

[ September 18, 2005, 04:20 PM: Message edited by: geezer ]