New store - "old work" - Holdzit straps?

[bjp_ne_elec]

Looked at a new commercial store, but the issue is it's already sheet rocked, and the guy leasing the store wants a bunch of new receptacles in the already finished walls. Really not liking the idea of putting "old work boxes in a brand new place. Anyone else have any better ideas?

I was actually thinking of cutting in old work boxes, but cutting out the sheetrock in front of the stud and using Caddy clips designed to hold boxes on the edges of the metal studs. Not really liking the thought of old work boxes and Holdzit straps.

Haven't bought MC cable in a while, as I was thinking of using MC on this job. Anybody know what a 250' roll of this has been going for? This store has 12' ceilings - not sure why the owner put 14' ceilings in. Know I need to buy some 12' step ladders - this "going in to the EC business is getting pricey. (Not sure, for those reading this, that I've had other posts - and I'm just getting a business started. Quite a different experience than "just doing the work".

Thanks


Brett

[petersonra]

old work boxes are made just for this situation.

it is unlikely anyone will ever notice much difference.

good luck in your new business.

never forget the important thing is to make a profit. all the neat new toys are meaningless otherwise.

[LarryFine]

. . . this "going in to the EC business is getting pricey. (Not sure, for those reading this, that I've had other posts - and I'm just getting a business started. Quite a different experience than "just doing the work".
You ain't seen nothin' yet!

The best of luck to you.

[JES2727]

I agree. Use old work boxes.
Last time I checked, 12-2 MC was about $128 at Home Depot, $140 at the supply house.

John

[LarryFine]

I agree. Use old work boxes.
Last time I checked, 12-2 MC was about $128 at Home Depot, $140 at the supply house.

John

And if you're using MC, I suggest metal old-work boxes with box supports, and a 90-deg. flex connector in the back KO of the box.

[bjp_ne_elec]

Larry - which box supports are you referring to? I like your suggestion about the 90 degree connectro - I had that same idea back several years ago, and had forgotten about how much easier it was until you mentioned it.

Thanks,

Brett

[satcom]

We use MC and metal switch box listed for use with MC, to support the box we use madison straps, neat and easy installation, reason we don't use a 90 connector in back of box is for one, the connector would be buried, and it places entry of wiring behind recpt. which can be a problem if using commercial grade recpt's.

[macmikeman]

Using a 90 deg flex connector inside a finished wall rings code alarm bells in my head, go read 350-20.

[iwire]

I agree with the others that pointed out a code violation installing 90 degree connectors in the wall.

I would use deep metal old works with MC clamps. Cut the hole tight and make sure you are gentle enough not to cause drywall 'blowouts' on the back side.

Install the Madison straps carefully and tightly as a final touch I use metal plates as they add a lot of support when people push the plugs in and have more depth to cover the box ears.

Pay attention to box fill, only one 12/2 cable per box.

Oh don't forget to cut the receptacle yoke to fit inside the box ears.

[roger]

When using cut in boxes with madison straps is a 90 deg flex connector really inaccessible?

If any of theses walls are fire walls the madison straps are out of the question.

Roger

[iwire]

When using cut in boxes with madison straps is a 90 deg flex connector really inaccessible?

I guess that depends on if you consider the box part of the building finish.;)

Honestly no, not by a strict reading of the definition. :)

Just not a fan of 'rear entry'.

If any of theses walls are fire walls the Madison straps are out of the question.

Good point.....one that is virtually unknown in my area.

Have a great forth of July Roger. :)

[roger]

Have a great forth of July Roger. :)

And you too Bob, and everyone else as well. http://electrical-contractor.net/ubb/icons/icon14.gif

Roger

[bjp_ne_elec]

Roger - what section of the code specfies you can't use teh madison straps? By the way, how did "madison straps" get their name? When working through my apprenticeship in NY, we always called them "holdzit" straps.

THanks,

Brett

[iwire]

what section of the code specifies you can't use teh madison straps?

Not the NEC it is more of a UL rated firewall assembly building code issue.

But if it is a double layer firewall and you cut a big hole to mount your boxes patching without overlapping seems is a pain in the rear as well.

[bjp_ne_elec]

Was going to edit my previous post, but Iwire already responded.

I would imagine that if it's a fire wall, then it's probably loaded with insulation as well. That brings up another interesting challange - and let's here how some of you would handle that challange.

One of the things with this job, is that the business owner is green. First when he called, he said he needed an electrician to give him an estimate on a "100 A" service added in a commercial building. So I'm thinking - no ladder needed when I show up to find out he wants 110 volt receptacles added around the place - and find 14' ceilings. We also looked at the panels and I quizzed him about the amount of breakers in the panel. The panel only had 14 circuits labeled, but the panel was almost fully loaded with breakers. Do they typically run homeruns throughout the ceiling in spaces like this, anticapating the the tenant will need to tap in to them at various locations?

He's dealing with some leasing broker, but doesn't have direct contact with the buildings owners. I've asked him to get a set of prints and see what we can find out about if any circuits are already sprinkled about. I think he's already got another price or two - so I'm not sure how the other guys bid it. If there are HR's that are already run around to cover the 10 - 12 circuits I need to establish, this will save needing to get up above the ceiling and run EMT. This would obviously reduce the bid, and the business owner's expense of the overall job.

THanks

Brett

[roger]

Brett, here is the UL info

WALL AND PARTITION ASSEMBLIES

Metallic Eletrical Outlet Boxes
Listed single and double gang metallic outlet and switch boxes with metallic or nonmetalliccover plates may be used in bearing and nonbearing wood stud and steel stud walls with ratings not exceeding 2h. These walls shall have gypsum wallboard facings similar to those shown in Design Nos. U301,U411, and U425. The metallic outlet or switch boxes shall be securely fastened to the studs and the opening in the wallboard facing shall be cut so that the clearance between the box and the wallboard does not exceed 1/8 in. The surface area of individual metallic outlet or switch boxes shall not exceed 16 sq in. The aggregate surface area of the boxes shall not exceed 100 sq in per 100 sq ft of wall surface.
Metallic boxes located on opposite sides of walls or partitions shall be seperated by a minimum horizontal distance of 24in. This minimum seperation distance between metallic boxes may be reduced when "Wall Opening Protective Materials" (CLIV) are installed according to the requirements of their Classification. Metallic boxes shall not be installed on opposite side of walls or partitions of staggered stud construction unless "Wall Opening Protective Materials" are installed according to the requirements of their Classification. the boxes must be fastened to the studs.

I don't know how all the names came about for Madison Straps, I have heard them called jiffy clips, steam ships, holdits, box holders and more.

Roger

[infinity]

Using a 90 deg flex connector inside a finished wall rings code alarm bells in my head, go read 350-20.


Article 350 in the 1999 NEC is for FMC not MC cable. Besides why would a 90 degree connector on a piece of MC cable be a violation? MC is not a raceway. There is nothing wrong with a 90 degree connector on MC cable.

[hillbilly]

Sometimes, if I'm concerned about a old work box staying secure, I will run a bead of liquid nails around the outside of the box (near the edge) before I push it into the wall.
Just a thought
steve

[larryl]

use 3 1/2" deep old work boxes,,get mad bars,,,,

[growler]

I doubt that liquid nails would be a good idea in a fire wall since the glue is flammable. Around here they let you use a fire rated putty on metal boxes. They sell it in squares that are 1/4" thick and just right for a 1900 box at Graybar. Cost about $2.00 to fire proof a box. bjp_ne_elect I have one bit of advice. If this owner is green then asked to see the other bids ( not the price quoted just the scope of work ), this will let you know if the others are planning on charging for new circuits and how many. If there are spare circuit you may be able to cut their price and still make some good money on the job. If you take the time to do the research you should be paid for it.

[LarryFine]

Larry - which box supports are you referring to?

The flat metal pieces others also call Madison clamps or straps. They're shaped somewhat like the Greek letter Pi. Like this: TT


Using a 90 deg flex connector inside a finished wall rings code alarm bells in my head, go read 350-20.

I just did. From the '02 NEC:

350.20 Size.
(A) Minimum. LFMC smaller than metric designator 16 (trade size 1⁄2) shall not be used.

Exception: LFMC of metric designator 12 (trade size 3⁄8)
shall be permitted as covered in 348.20(A).

(B) Maximum. The maximum size of LFMC shall be metric designator 103 (trade size 4).

FPN: See 300.1(C) for the metric designators and trade sizes. These are for identification purposes only and do not relate to actual dimensions.


Oh don't forget to cut the receptacle yoke to fit inside the box ears.

Good reminder!


When using cut in boxes with madison straps is a 90 deg flex connector really inaccessible?

Not to me: just unbend the supports and pull the box out of the wall. Even a junction box behind a kitchen cabinet is accessible.


Just not a fan of 'rear entry'.

Now, we're gettin' personal!


By the way, how did "madison straps" get their name?

My guess is that it is, or was, a company name, like Tomic and Mineralac.

[77401]

OWB with sheetrock clamps ( Madison clamps is the name of the clamp up north, Down here we don't know any body by the name of Madison)
No connector needed if box is listed for AC or MC cable. why add another cost & labor wasting step to the install.

[tufts46argled]

We call'em F clips!

[e57]

Don't you guys mean "Battleships"?
http://www.erico.com/public/images/products/FF-Electrical/NorthAmerica/127675.jpg

As far as fire walls go, using old work boxes, installing pads on the boxes will be impossible. Why not roto-zip a wide hole, then a smaller hole for each box.... Leave the pieces you cut out screwed to the wall for "Others" to patch. "Patching, Fire-Proofing and Painting Not In Contract." If dealing direct with customer as opposed to a GC just inform them of the paramiters and tell the to hire a proffessional rocker and taper outfit.

[hardworkingstiff]

My guess is that it is, or was, a company name, like Tomic and Mineralac.

Are "Tomic" connectors still around? A few years ago I asked a couple of supply houses if they had any or could get some and I got the deer in the headlight look. Apparantly Tomic connectors never made it into the Wilmington, NC area.

[Smart $]

By the way, how did "madison straps" get their name?
My guess is that it is, or was, a company name, like Tomic and Mineralac.
You are correct: Madison Electric Products (http://www.fittings.net/about.asp)

[macmikeman]

quote" Article 350 in the 1999 NEC is for FMC not MC cable. Besides why would a 90 degree connector on a piece of MC cable be a violation? MC is not a raceway. There is nothing wrong with a 90 degree connector on MC cable.
__________________
Trevor "

Trevor, you are absolutely right, thank you for finding my error.

[bjp_ne_elec]

I should find out this Friday, but let's assume one of the walls (the one that seperates two stores) is a firewall. How would you handle the MC cable? I was just thinking of punching through the sheetrock just above the dropped ceiling line and fishing down the wall. It's odd know thinking back when I wasn't the "Master" how I dealt with "small details" (actually very important details) - but I was mostly on larger jobs where the architect and those you needed to run things by were around. It's amazing when you move to a smaller scale, of the things you really have to cover on your own.


THanks,

Brett

[bjp_ne_elec]

Found out this job is double-rocked ( 2 - 5/8") and to top it off, he wants Quad Receptacles. I don't see using OW boxes any longer. Anyone disagree?

Looks like I'm going to have to put my Dewalt DC550 to work buzzing holes next to the metal studs.

BRett

[77401]

Why not gang up the OWB?

I have bought the sheetrock clamps(maddy straps) with the long ears on them that can fit double rock.

[satcom]

I would just run 1/2" EMT down the wall and surface mount the boxes. Let them paint it if they like.

[roger]

Brett, being that the walls are double layers of 5/8 sheetrock, there is a better than average chance they are rated so fastening to the stud will be necessarry. Putty pads may or may not be necessary, (depends on the number of boxes in a given area) but sealing your MC or AC with a fire caulk should be done.

Roger

[roger]

Actually Satcom has the best idea. Wiremold may be another option.

Roger

[satcom]

By running surface, it can easly be removed, most strip malls we do, the building owner wants us to surface mount.

[bjp_ne_elec]

I'm dealing with an inspector I've never dealt with before, and I didn't get a warm response when I mentioned OW boxes. But when we were finishing up the conversation, he made a comment that "you're allowed so many penetrations in a firewall" - so I took that as maybe OW's would possibly be allowable. I think I'm going to put together a layout and run it by him for "pre-approval". I don't want to cut OW's in between the studs and then have him reject them - as then is would be "patch city" in the rock.


I've never used Maddy clamps with double rock - have to see if the local supply house has them.

I like the EMT idea. Never used EMT on surface of sheetrock personally. I have to ask - how do you mount the boxes - directly through the rock into studs? As I've never ran anything surface mount on rock - in my own past experienses - are there any restrictions on how you anchor boxes or conduit to the rock. For mounting other than electrical - I personally love those plastic (not sure what they're officailly called) anchors that screw directly in to the rock. Just drive a #2 Phillips in to the rock and screw the bad boy home.

Thanks

Brett
Brett

[growler]

Sure, if they will let you surface mount, go with that. It's easier and faster than fishing. If they haven't painted and you can see where the studs are just use 2" sheet rock screws and screw right to the studs. 1900 boxes and raised covers for those quads. Make sure the tenant agrees to surface mount in writing. Make sure they know it's not your job to paint conduit or to tape off receptacles for paint. Give the customer the options and let them make the decisions. See if these receptacles need to Meet ADA height requirements. Normally if you stay above 18" to center you are good ( check anyway ).

[bjp_ne_elec]

According to the customer, the some of the receptacles are to be mounted at 48" (just above a work counter) and the others at 7'-8', as these are for LCD screens that he's going to hang there.

Have to ask - what is "ADA Height"? AHJ - is Authority Having Jurisdiction.

Growler - excellent suggestion about the painting of conduit and the taping off of receptacles. It's those finer points that could burn you, and again, I'm really green with this EC thing - so again, excellent tip!

I'm seeing almost a 50/50 split as to whether OW boxes would fly in the firewall. Some folks are saying "no, they can't be used" - while others are saying "they're fine" - and then I just get this look from the Inspector when I mention them, that didn't even want me to ask another question.

Anyone have any nifty ways of supporting multiple runs of MC? All my experience as a Journeyman was running either EMT or Rigid. The only thing I ever used flex for was for tails to drop-in light fixtures.

THanks,

Brett

[roger]

Brett, if the original walls have a UL design attached to them (you would need to see the original drawings for this design type) and you decide to mount the boxes in the walls, then to keep the assembly in line with the design type, the boxes would have to be attached to the studs (per UL) regardless of what any one says, even an inspector. These boxes can be OW boxes.

ADA = Americans With Disabilities Act

Roger

[iwire]

Anyone have any nifty ways of supporting multiple runs of MC?

Caddy (a division of Erico) and B-Line both have a lot of products for that.

Get some catalogs or find them on the web.

[Smart $]

...[inspector] made a comment that "you're allowed so many penetrations in a firewall"
You should determine if he is the AHJ on firewall penetrations (if you penetrate). An electrical inspector may not be the AHJ on the issue... may be the Fire Marshal.

[Bob NH]

A method that I have found effective that might be useful here is as follows:

1. Surface mount is the cleanest way to go, and apparently the AHJ doesn't really like the idea of OW boxes.

2. So get an understanding with the AHJ/Inspector that OW Boxes are not acceptable from a fire safety point of view; then

3. Tell the tenants and owner that surface mount is the only thing that will be acceptable, short of tearing out a lot of stuff at great expense and making it "like new".

The tenants and owner will make the decision you want.

You have to be sure the inspector is solid and won't undercut you after you sell the story.

[bkludecke]

Wow what an interesting thread. I've follwed this one for a few days. I would have given up and used Wiremold a long time ago. Once you get used to it Wiremold "500" is agreat product. It looks clean and professional if you do it right. We even have a Wiremold bender and cutting tool to make things easy. The fittings and accessories are endless.

Bob on the left coast.

[bjp_ne_elec]

I think I have the owner convinced wiremold is the way to go, but I'm a little confused on Roger's comment - "the boxes would have to be mounted to the studs (per UL)" - not sure why this is. The other problem I see, if this is true, is that the boxes won't line up consistenty with the five stations that have to be wired.

There is not approved way to anchor to sheetrock in a situation where the wall is a "firewall"? Again, I've been maybe a little spoiled, as all of my experience, as far as commercial, has been in brand new construction - so with this one, if I could have been in there when the space was being roughed - I would have been in "Caddy city" with the whole job. MC Cable throughout.

But then again - you know what they say - "if it was going to be easy your mother would be doing it" (or something similar - not that my mother or anybody else's mother couldn't have wired this one).



Thanks,

Brett

[roger]

Brett, here it is one more time.

Quote:
WALL AND PARTITION ASSEMBLIES

Metallic Electrical Outlet Boxes
Listed single and double gang metallic outlet and switch boxes with metallic or nonmetalliccover plates may be used in bearing and nonbearing wood stud and steel stud walls with ratings not exceeding 2h. These walls shall have gypsum wallboard facings similar to those shown in Design Nos. U301,U411, and U425. The metallic outlet or switch boxes shall be securely fastened to the studs and the opening in the wallboard facing shall be cut so that the clearance between the box and the wallboard does not exceed 1/8 in. The surface area of individual metallic outlet or switch boxes shall not exceed 16 sq in. The aggregate surface area of the boxes shall not exceed 100 sq in per 100 sq ft of wall surface.
Metallic boxes located on opposite sides of walls or partitions shall be separated by a minimum horizontal distance of 24in. This minimum separation distance between metallic boxes may be reduced when "Wall Opening Protective Materials" (CLIV) are installed according to the requirements of their Classification. Metallic boxes shall not be installed on opposite side of walls or partitions of staggered stud construction unless "Wall Opening Protective Materials" are installed according to the requirements of their Classification

This is word for word out of the UL orange book set, the FIRE RESISTANCE DIRECTORY, the same set of books that has the criteria for the rated wall itself. Notice there is no wording that will allow any thing but fastening the boxes to the studs period.

If an inspector is saying it is okay to do otherwise he is not aware of this requirement, but it will not relieve you from some level of liability if something were to happen, especially now that you have read it from UL's own literature.

Roger

[77401]

Roger
I don't think this is refering to a surface mounted Wiremold system. but is in refernece to new installations.

Bret you should not need to anchor to the studs, just use plastic achors or the white screw in hollow wall anchors & the WM will be securly fastened.

[bjp_ne_elec]

77401 - I'm hoping your feedback is correct, but I don't even want to turn the bid in (am supposed to turn it in tomorrow - Monday) until I get this nailed. My lack of experience in "add-on" in the commercial world is going to be one of the biggest negatives against me, as far as getting my business going. I think this could be a nice job, and I need to "win" a few to start getting customer referrals. My feeling is that the commercial side can be pretty lucrative.

What causes you to comment on Roger's feedback - where you indicate that Roger's reference is only for new installations?

Thanks,

Brett

[77401]

Its a code thing about having back to back outlet boxes inside a firewall. For Example if a fire in my space penetrates my outlet box & between the same studs is an outlet box in your space then the fire can penetrate to you easily.
Besides commons sense says... How is anyone(inspector)but the installer going to know if your anchored into a wall stud as long as the boxes & raceway are secure.
You see it the inspector walks in & out in 2 minutes max.

Many times common sense has tp predeced code, not eliminate it.

[tkb]

Brett, here it is one more time.

Quote:
WALL AND PARTITION ASSEMBLIES

Metallic Electrical Outlet Boxes
Listed single and double gang metallic outlet and switch boxes with metallic or nonmetalliccover plates may be used in bearing and nonbearing wood stud and steel stud walls with ratings not exceeding 2h. These walls shall have gypsum wallboard facings similar to those shown in Design Nos. U301,U411, and U425. The metallic outlet or switch boxes shall be securely fastened to the studs and the opening in the wallboard facing shall be cut so that the clearance between the box and the wallboard does not exceed 1/8 in. The surface area of individual metallic outlet or switch boxes shall not exceed 16 sq in. The aggregate surface area of the boxes shall not exceed 100 sq in per 100 sq ft of wall surface.
Metallic boxes located on opposite sides of walls or partitions shall be separated by a minimum horizontal distance of 24in. This minimum separation distance between metallic boxes may be reduced when "Wall Opening Protective Materials" (CLIV) are installed according to the requirements of their Classification. Metallic boxes shall not be installed on opposite side of walls or partitions of staggered stud construction unless "Wall Opening Protective Materials" are installed according to the requirements of their Classification

This is word for word out of the UL orange book set, the FIRE RESISTANCE DIRECTORY, the same set of books that has the criteria for the rated wall itself. Notice there is no wording that will allow any thing but fastening the boxes to the studs period.

If an inspector is saying it is okay to do otherwise he is not aware of this requirement, but it will not relieve you from some level of liability if something were to happen, especially now that you have read it from UL's own literature.

Roger

I dont thik this applies to surface mounted boxes, only boxes IN the wall.

I would use toggle bolts with fire caulk in the holes.

Tim

[growler]

All Roger is saying is that you can't use old work boxes because they can not be fastented to the stud. Remember to use an old work box you have to make a hole in the wall. The only thing holding that box are a couple of little straps. I'm sure that everyone has seen old work boxes pushed back in the wall leaving a hole that would damage the fire rating. When you surface mount boxes then you are not making any holes in the wall. I use sheet rock screws because they are cheap and fast. If you don't know where the studs are then use anchors ( they even make a metal version of those screw in anchors). Don't let work scare you just because it's new to you, that's how you learn. 30 years and still learning.

[bjp_ne_elec]

Roger- can you jump back in the mix here, and see if you agree with what growler said? Just want to see if we can get a consensus on this one, as it could drastically impact my bid.

Thanks

Breett

[roger]

Okay, it appears as though people didn't read the words in the my post of 7-7-06 at 6:03 AM, before I said "the boxes would have to be attached to the studs (per UL)". The words in part before that were "and you decide to mount the boxes in the walls", this is what my statement was based on.

Brett, as far as mounting on the surface, I don't know of anything that would prohibit easy anchors (zip its) or toggle bolts, but in my local area we always try to find a stud to run screws into if possible as mentioned by Growler.

Roger