SO Cord drop for car lift in mechanics garage

[vino82]

I mostly work in the residential field and I was recently asked to do a bit of work in a mechanics garage. They have installed a new car lift and looking at the existing lifts there is a J. Box on the ceiling with a piece of SO cord dropped down to the twistlock connector at the lifts motor. There is a strain-relief at the top where the SO terminates into the J. Box. I plan to copy this installation but I am a bit concerned about a couple of things. <BR><BR>1. I can't find in the code where SO is allowed in this situation. <BR><BR>2. This being a mechanics garage designates it as a Class 1 Division 2 setting (explosion proof required) looking up at the ceiling I see standard 4" sq. boxs... <BR><BR>3. I can run my new circuit above the ceiling in MC where I plan to come through the ceiling into an approved box and dropping my SO cord from there, can I run MC above the ceiling in a crawl space? <BR><BR>4. The panel is fully loaded with old GE breakers, there is an unused 3-pole breaker that I intend to use as a 2-pole breaker, can I do that?<BR><BR>Thank you

 

[Dennis Alwon]

There is no problem with using 3 pole as a dp breaker. I will let the others answer the other questions. I have seen rubber cord used in garage so I don't think it is an issue but it may depend on the type of garage.

 

[rbalex]

There are multiple issues, but the most pressing is an accurate determination of the electrical area classification and that depends on the scope of the repairs performed.

See Section 511.2 to determine whether this will be a major or minor repair garage. The distinction is not size but types of repairs performed. Also check whether fuel dispensing will be performed. That will determine if Sections of Article 514 will also apply.

Section 511.3 will determine the actual electrical area classifications. You may be surprised that the classification envelope is not as large as you imagine. In any case, it must be properly documented are required by Section 500.1(A).

The above is said because the SO cord may not actually be in a classified location. However, there are certain requirements for wiring above, but not necessarily in, a classified location in garages. See Section 511.7 in general. SO cord is fine but I strongly recommend installing it per Sections 501.140 and 501.145 although it isn’t an absolute necessity. (The cost differential is minimal and you'll sleep better) See Section 511.7(A)(2) specifically.

The new circuit doesn’t need to be above the ceiling, if it is consistent with Section 511.7(A)(1). Personally, the existing installation sounds compliant, but I don't know for certain.

 

[vino82]

Regarding 511.2 I'm going to say it is a major repair garage, no fuel dispensing.

511.3 applies because gas may be drained from trucks among other fluids, but I go on to read...

according to the requirements of 511.3 (C)(1)(b) ventilation is not provided (although the lift is positioned a few feet away from the garage door) but it states that the floor area up to 18"shall be classified as C1 D2... Does that mean everything 18"and above is classified C1 D1?

consider it a minor repair garage would the area be considered unclassified because there is no subfloor, belowgrade work taking place?

One more query... Does unclassified mean I do not need to install explosion proof boxs and run threaded rigid? As if hazardous locations no longer apply?


Thanks for helping this house mouse learn his way around some commercial projects.

 

[rbalex]

Major repair, no despensing, no ventilation = Class I, Divison 2, from floor to 18" above the floor and Division 1 in any pits. The rest of the location above 18" is unclassified. Explosionproof is not required in unclassified locations, but take care to observe Section 511.7 and locating equipment per other Sections of Article 511. It isn't a long Article, read it all. Read Article 510 (it's even shorter) as well to understand the relationship of Article 511 to Articles 500 and 501.

 

[vino82]

Much obliged for your insight into the code.

I read 511 and it appears to me that I am good to go installing 4" sq box on the ceiling and running MC above the ceiling. 18" and above unclassified, all my work is taking place above 18". I am going to look into cord that is listed for "hard usage" for my drop to the car lift.

 

[kwired]

I question whether or not flexible cord is permitted to connect this equipment.

Look in 400.7 and 400.8

400.7(A)(7):
(7)

Prevention of the transmission of noise or vibration

Is about the only one in the list of uses permitted that may apply.

Automobile hoists typically are not portable, are not frequently interchanged, and the allowance for connection of moving parts would apply to moving parts on the hoist not the supply conductors between the premises wiring and the utilization equipment.

 

[sgunsel]

Most hoists used today can be considered portable, even if they do not move around, so flexible cord is probably OK. Check with the inspector, LFMC is just about as easy. Don't forget to GFCI the receptacles.

 

[kwired]

Most hoists used today can be considered portable, even if they do not move around, so flexible cord is probably OK. Check with the inspector, LFMC is just about as easy. Don't forget to GFCI the receptacles.

You have to draw the line at what is normally considered portable. We have the technology and ability to make almost anything portable. So maybe we should use flexible cord for everything including services and feeders.

Most automobile repair shops I have been in if a hoist is moved there is either rennovations happening or the same hoist is not coming back.

 

[rbalex]

I undersand the application as stated in the OP is a pendant mounted cord cap. Sections 400.7(A)(1), 501.140, 501.145, 511.7 A)(2) are applicable. So is 90.3, first paragraph, last sentence Edit add: Consider it an amendment.


There is nothing wrong with a pendent mounted, twistlock cord connection using extra hard usage cord as described.

 

[rbalex]

Much obliged for your insight into the code.

I read 511 and it appears to me that I am good to go installing 4" sq box on the ceiling and running MC above the ceiling. 18" and above unclassified, all my work is taking place above 18". I am going to look into cord that is listed for "hard usage" for my drop to the car lift.

There are several "hard usage" and "extra hard usage" cords and cables listed in Table 400.4. Some are even specifcally rated for "Hazardous (classified) locations" but be careful they also have "hard usage" or "extra hard usage" listed in the "Use" column.

There are several options, but Type SO is generally one of the most readily available.

 

[vino82]

I agree with rbalex. Looking at 400.7 (A)(10) "Where specifically permitted elsewhere in this code"

501.140 (A)(2) "...where the fixed wiring methods of 501.10(A) cannot provide the necessary degree of movement for FIXED and mobile electrical utilization equipment...

501.140(B) requires listed extra-hard usage cord (which is what I ask? my supply house doesnt know of listed cord "extra-hard usage" im looking at SEOOW cord now...

the lift is located central in the room and the ceilings are over 20' high. If I was to run threaded rigid conduit to the lift motor from the ceiling I would need to build a structure from the ceiling to floor to properly secure the pipe.

Thanks for the input.

 

[vino82]

I see table 400.4. fantastic. thanks

 

[Electchicken]

The so cord

The so cord

I have ran into this many times and seening this fail will happen. A strain relief is not good enough to hang a cable from the ceiling with. You need a horse cock or kelm grip tech screwed to the ceiling for the added support, this should be good for 20 years. Strain reliefs are good for horizontal cables but not vertical. This is for certain with rammy mechanics who will pull that cord out of the strain relief just to get the extra inch out of the cable instead of getting a longer extension cord. I agree with the others about the area class. The roof is a general area, but as you get to the floor area it's classed. I use the CEC, so I'm not sure the height they'd class it in America.

 

[Speshulk]

Much obliged for your insight into the code.

I read 511 and it appears to me that I am good to go installing 4" sq box on the ceiling and running MC above the ceiling. 18" and above unclassified, all my work is taking place above 18". I am going to look into cord that is listed for "hard usage" for my drop to the car lift.

Seems as though you could save yourself a lot of aggravation if you just ran the original MC from the ceiling all the way down the lift and installed a twist lock receptacle on the lift.

 

[Cow]

Right or wrong, I installed car lift cord just as you described. I also copied the other existing lifts wiring. I used a hoop type strain relief screwed to the structure rather than using the CGB's with integral strain relief out of the 4 sq box.