jimwalker
Senior Member
- Location
- TAMPA FLORIDA
Just what is the support/fastening rules if we use MC cable to daisey chain light fixtures 2x4 inlays
daisy chain
- Thread starter jimwalker
- Start date
- Status
jimwalker
Senior Member
- Location
- TAMPA FLORIDA
Re: daisy chain
Roger thanks,i thought that was how it was but being told i must support within 1 foot of fixture except if its a 6ft whip and then being told i need 1 strap near junction box.Will run this thru inspector
Roger thanks,i thought that was how it was but being told i must support within 1 foot of fixture except if its a 6ft whip and then being told i need 1 strap near junction box.Will run this thru inspector
- Location
- Illinois
- Occupation
- retired electrician
Re: daisy chain
Roger,
I don't think that the actual code wording in that section permits the use of MC or AC cable as fixture whips. The code section says that there can be 6' of cable from the last point of support to the fixture. In the cable on the left in Mike's graphic there is no support. This problem is caused by a wording change from the 99 code to the 02 code. Here is the text from the 99 code.
Don
Roger,
I don't think that the actual code wording in that section permits the use of MC or AC cable as fixture whips. The code section says that there can be 6' of cable from the last point of support to the fixture. In the cable on the left in Mike's graphic there is no support. This problem is caused by a wording change from the 99 code to the 02 code. Here is the text from the 99 code.
And from the 02 code:
In the 99 code it was permitted to use the cable as a fixture whip as the code section did not require any support in this application. The wording change in the 02 code requires at least one support on the cable being used as a fixture whip.
Don
Re: daisy chain
Don, help me out, what does "last point of support for connections" mean? I understand wording such as "Type MC cable shall be supported and secured at intervals not exceeding 1.8 m(6 ft)" but I have never (or very rarely) intentionally supported a connection.
It seems as though the "last point of support for connections" is actually be the luminaire or equipment?
Roger
Don, help me out, what does "last point of support for connections" mean? I understand wording such as "Type MC cable shall be supported and secured at intervals not exceeding 1.8 m(6 ft)" but I have never (or very rarely) intentionally supported a connection.
It seems as though the "last point of support for connections" is actually be the luminaire or equipment?
Roger
- Location
- Illinois
- Occupation
- retired electrician
Re: daisy chain
Roger,
I'm not really sure, but my opinion is that it is a point of support for the cable itself. My take on the 02 wording is that if you are using the cable as a fixture whip, then you must provide one support for the cable, and this seems to be what Jim's inspector is asking for.
Don
Roger,
I'm not really sure, but my opinion is that it is a point of support for the cable itself. My take on the 02 wording is that if you are using the cable as a fixture whip, then you must provide one support for the cable, and this seems to be what Jim's inspector is asking for.
Don
buck33k
Senior Member
- Location
- Washington state and North Carolina
Re: daisy chain
It seems like the graphic would apply to FMC and 348.30(A) exception 3, because of the difference in wording and reference to 410.67(C).
It seems like the graphic would apply to FMC and 348.30(A) exception 3, because of the difference in wording and reference to 410.67(C).
Re: daisy chain
[ October 22, 2004, 02:53 PM: Message edited by: jap2525 ]
In my opinion the only thing supporting the flex in this drawing is the ceiling tile not the connectors.This is a drawing of unsupported cable.Originally posted by roger:
Don, who is going to tell Mike his graphic is wrong and the center fixture is the only one of the fixtures code compliant?
Roger
[ October 22, 2004, 02:53 PM: Message edited by: jap2525 ]
Re: daisy chain
Point is,,,,,,there seems to be no clear answer on how to support mc cable or flex when it comes to daisy chaining light fixtures.Inspectors here have us ziptye the mc cable to the ceiling grid wires even though they are not intentionally installed for this purpose.To me mc cable and flexible conduit is installed for that pupose,,,,,,,flexibility,,,,,,,,why are we supporting it? To keep it from pulling out of the connectors? to keep it up off of the ceiling tile?
Point is,,,,,,there seems to be no clear answer on how to support mc cable or flex when it comes to daisy chaining light fixtures.Inspectors here have us ziptye the mc cable to the ceiling grid wires even though they are not intentionally installed for this purpose.To me mc cable and flexible conduit is installed for that pupose,,,,,,,flexibility,,,,,,,,why are we supporting it? To keep it from pulling out of the connectors? to keep it up off of the ceiling tile?
Re: daisy chain
Jap, I also question why a length no more than 6' in an installation as shown in the graphic would need supporting. Two fixtures seperated by a 2' tile with the KO's in the center and served with a 6'length of cable would not pose a problem if it were laying on the ceiling.
If the NEC does not require fixtures to be independantly supported from the structure leaving only the ceiling itself supporting them, then why would a little slack of cable need to be supported?
I agree with Mikes interpretation as shown in the graphic and not because it's from Mike.
FWIW, I'll disagree with anybody if it's heart felt.
Roger
Jap, I also question why a length no more than 6' in an installation as shown in the graphic would need supporting. Two fixtures seperated by a 2' tile with the KO's in the center and served with a 6'length of cable would not pose a problem if it were laying on the ceiling.
If the NEC does not require fixtures to be independantly supported from the structure leaving only the ceiling itself supporting them, then why would a little slack of cable need to be supported?
I agree with Mikes interpretation as shown in the graphic and not because it's from Mike.
FWIW, I'll disagree with anybody if it's heart felt.
Roger
Re: daisy chain
I think this rates right up there with conduit supported within 3' of a box.What is the support of a conduit within 3' of the box? More than likely a mineralac strap,one hole strap,strut strap or some other kind of strap.Why? I don't know.It's not like a peice of pipe will fall apart if this support is not located within that distance.You could take the strap out and the pipe would still support itself.Therefore I believe support has more to do with professional workmanlike installations rather than nitpicking where a support should be installed in relation to distance.I also feel like a lot of the 6' flex rules talked about in the code partain to old time installations that did not include a ground wire in the installation and was using the flex as a ground return path.We install mc or flex or conduit with a ground wire with our installations regardless of the type of conduit which takes the 6' rules for grounding out of the equation in most cases,but not for support.
I think this rates right up there with conduit supported within 3' of a box.What is the support of a conduit within 3' of the box? More than likely a mineralac strap,one hole strap,strut strap or some other kind of strap.Why? I don't know.It's not like a peice of pipe will fall apart if this support is not located within that distance.You could take the strap out and the pipe would still support itself.Therefore I believe support has more to do with professional workmanlike installations rather than nitpicking where a support should be installed in relation to distance.I also feel like a lot of the 6' flex rules talked about in the code partain to old time installations that did not include a ground wire in the installation and was using the flex as a ground return path.We install mc or flex or conduit with a ground wire with our installations regardless of the type of conduit which takes the 6' rules for grounding out of the equation in most cases,but not for support.
A
a.wayne3@verizon.net
Guest
Re: daisy chain
Jap2525 I have often wondered why is it ok to fish nm in a void but it has to be secured and protected on a rough in ,300.4 D is to stop nail damage.A loose piece of NM is not subject to physical damage ??? Toggle bolts come to mind.In a perfect world the gray areas would not be there ,but this is the NEC
Jap2525 I have often wondered why is it ok to fish nm in a void but it has to be secured and protected on a rough in ,300.4 D is to stop nail damage.A loose piece of NM is not subject to physical damage ??? Toggle bolts come to mind.In a perfect world the gray areas would not be there ,but this is the NEC
jimwalker
Senior Member
- Location
- TAMPA FLORIDA
Re: daisy chain
I think romex would actually be safer with no staples.It would likely get pushed out of the way with a toggle bolt.And no shorting out if staple too tight.
We will see what happens in a few days on this job.It is a 27 year old building that has had maintenance men adding wiring and repairs.We have spent days trying to secure old emt and whips.There are some old runs of emt that are supported only with grid wire and laying on AC ducts.I have removed about 600 feet of unused unsecured emt.
I think romex would actually be safer with no staples.It would likely get pushed out of the way with a toggle bolt.And no shorting out if staple too tight.
We will see what happens in a few days on this job.It is a 27 year old building that has had maintenance men adding wiring and repairs.We have spent days trying to secure old emt and whips.There are some old runs of emt that are supported only with grid wire and laying on AC ducts.I have removed about 600 feet of unused unsecured emt.
pierre
Senior Member
- Location
- Westchester County, New York
Re: daisy chain
The 05 NEC has new language that tries to clear up the muddled wording of support/securing of AC/MC cables.
.30(D)(2) recognizes that for the purpose of this section, Types AC and MC cable fittings are permitted as a means of cable support.
Therefore Mike's illustration will now truly meet code
Pierre
The 05 NEC has new language that tries to clear up the muddled wording of support/securing of AC/MC cables.
.30(D)(2) recognizes that for the purpose of this section, Types AC and MC cable fittings are permitted as a means of cable support.
Therefore Mike's illustration will now truly meet code
Pierre
pierre
Senior Member
- Location
- Westchester County, New York
Re: daisy chain
This brings me back to a question I asked before.
Can I as an inspector, be able to use the new language in this section to help clear up the intention of previous code cycles, while inspecting work filed under previous code cycles, such as '99, '02?
Is this new language the intention of the past language?
Pierre
This brings me back to a question I asked before.
Can I as an inspector, be able to use the new language in this section to help clear up the intention of previous code cycles, while inspecting work filed under previous code cycles, such as '99, '02?
Is this new language the intention of the past language?
Pierre
Re: daisy chain
While I am not an inspector, I would think that any wording or experiance would come into play on making a judgement on whether an instalation was safe. Correct me if I am wrong, I know you will, but is not the intent begind the code to make for safe instalations? I recently went to the Bahamas to work doing clean up after the hurricanes, they are governed by the Candian Electric Code. What impressed me about this code was that for every rule there was an intent right above it. So you not only looked at the rule but why it was there. Makes sense to me and made the book much easier to use than our NEC.
While I am not an inspector, I would think that any wording or experiance would come into play on making a judgement on whether an instalation was safe. Correct me if I am wrong, I know you will, but is not the intent begind the code to make for safe instalations? I recently went to the Bahamas to work doing clean up after the hurricanes, they are governed by the Candian Electric Code. What impressed me about this code was that for every rule there was an intent right above it. So you not only looked at the rule but why it was there. Makes sense to me and made the book much easier to use than our NEC.
ryan_618
Senior Member
- Location
- Salt Lake City, Utah
Re: daisy chain
Pierre: I think yoou and I see eye to eye on this subject. This is an example of where I think the AHJ is able to use a future code rule in an effort to clarify an existing problem. i would have no problem using this right now, becasue as you said, it is not 100% clear in the 2002.
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