mc suport in suspended celings feeding luminaires
- Thread starter jkrauss
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mike7330
Senior Member
- Location
- North America
Yes it does, within 12 inches of box. Clamp it, strap it, ... To the support you are using for the box.
jimdavis
Senior Member
- Location
- salt lake city, UT USA
I disagree. According to 330.30(D) the mc connector itself qualifies as a means of support in this application. Therefore a 6' length of mc cable running between a junction box and a luminaire would require no additional support.
- Occupation
- Licensed Electrician
I agree with the disagreement. Six feet = no strap.
Michaelmechanic
Member
- Location
- Ft lauderdale fl Lu 728
No strap. But if you daisy chain then it becomes a raceway and needs a strap
- Location
- Massachusetts
No and no.
kwired
Electron manager
- Location
- NE Nebraska
Not sure but guessing this is the same in 2014, here is what is in the 2014:
"Is not more than 1.8 m (6 ft) in length from the last point of cable support to the point of connection to luminaires or other electrical equipment and the cable and point of connection are within an accessible ceiling. For the purpose of this section, Type MC cable fittings shall be permitted as a means of cable support."
Last point of cable support would have to be the connector on the last junction box or last luminaire if daisy chained. If the length is 6 feet or less it is saying no additional support is needed but it must also be within an accessible ceiling. There is similar rules for flexible conduits and for other cable types as well.
How does it become a raceway? It is still a cable wiring method regardless or length or installation methods.
Michaelmechanic
Member
- Location
- Ft lauderdale fl Lu 728
I read the article and you are right. I was taught that only out of a jbox and less than 6 ft need not be supported. But if u go fixture to fixture it had to be strapped .
kwired
Electron manager
- Location
- NE Nebraska
If you go fixture to fixture and length is less then 6 feet no additional strapping should be necessary, but wouldn't be prohibited either.
Biggest thing that often discourages the fixture to fixture method is use of FMC as the EGC is not allowed over six feet of total EGC path, and then people kind of get it in their head that fixture to fixture just isn't allowed an forget exactly why the generally don't do it, plus the support rules sneak in there as well.
Biggest thing that often discourages the fixture to fixture method is use of FMC as the EGC is not allowed over six feet of total EGC path, and then people kind of get it in their head that fixture to fixture just isn't allowed an forget exactly why the generally don't do it, plus the support rules sneak in there as well.
kwired
Electron manager
- Location
- NE Nebraska
The support rule is same/similar for most other cables or flexible raceway wiring methods.
electricalist
Senior Member
- Location
- dallas tx
I thought if it were from a j box and flexed down to the light and under 6' no strap was needed and mc / aluminum had to be strapped 12" from termination. Nothing can be laying on grid as means of support there for independant ceiling wires must be used connected at both ends not because its an electrical code but a bldg code. Ceiling grid manufacturer would have to sing off saying the grid is rated to hold the mc
Not per the NEC. Read all the 3XX.30 sections.
With that being said, local building codes may be another story and 410.36 may be of some interest too.
Roger
arcsnsparks98
Senior Member
- Location
- Jackson, TN USA
Caddy makes these awesome little clips just for securing mc to the grid. They hold it in place quite nicely and, when installed properly, do not interfere with removing the tile.
electricalist
Senior Member
- Location
- dallas tx
I must have missed something. I didnt know a connector could be used as a means of support. But I thought what I said was the same as 300.11
kwired
Electron manager
- Location
- NE Nebraska
I don't see what 300.11 has to do with a connector being used as a means of support. I will say in a situation where no other support means is necessary that kind of leaves the connector tasked with providing support to at least some extent.
I must have missed something. I didnt know a connector could be used as a means of support. But I thought what I said was the same as 300.11
electricalist
Senior Member
- Location
- dallas tx
Someone said my statement was not true by nec code and that 300.11 would help. Sorry if I misunderstood
kwired
Electron manager
- Location
- NE Nebraska
300.11 does address supporting of wiring methods, but doesn't address connectors being allowed as the support method, yea or nay, and doesn't cover the six feet of unsupported methods allowed in specific instances. You have to read other sections to answer some of those questions.
electricalist
Senior Member
- Location
- dallas tx
Ty sir
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