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Wire Transitions Between Crawl Space and Garage, and Crawl Space and Breaker Box

Wire Transitions Between Crawl Space and Garage, and Crawl Space and Breaker Box

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  #1  
Old 05-13-12, 11:18 AM
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Wire Transitions Between Crawl Space and Garage, and Crawl Space and Breaker Box

Hi,

First time poster. I did some searching; but, nothing specific jumped out at me, so I thought I would post my situation and see if someone might be able to advice me.

Basically, what I am doing, is adding three circuits into my garage. Two will be 110 VAC (20A), the third will be 220 VAC (40A). I will be replacing some existing 20A breakers with tandem breakers in the breaker panel as there's no room on the existing panel bus to add additional circuits. (The present panel is a 200A service.)

I have been advised by a business associate who knows the NEC pretty well. I have also asked questions at my local Home Depot.

This morning I ran the wiring in the crawl space. (One of my least favorite places to work.) I am using 8 gauge for the 220, and 12 gauge for the 20A. I drilled the joists (following rules I read in other threads) and ran the wire through the joists. (I kept the holes to 3/4", and I used two in each joist. One for the 220 wire and the other for the 110 wires.)

Now for my predicament.... running the wire into the breaker box at one end, and into the garage wall on the other end. I doubt it's really too difficult for someone with experience. I'm just a little out of my comfort zone. I don't want to make a mistake, either.

Here are the details:
  1. From the Crawl Space to the Breaker Box – The only concern that I have on this end of the circuit is getting up into the wall. There is a pretty large knock-out on the bottom of box that I should be able to use. The concern that I have is drilling up into the wall without hitting anything else. There are only two circuits that come out into the crawl, everything else goes out the top of the panel. My thought is that I should be able to move over about 4” and I should avoid those wires. Then I’ll work on getting something fished down from the top… with some patience. Sound like a good plan?
  2. From the Crawl Space to A Garage Wall – This is the hard one! To make a long story a little shorter, there is really only one good location to run the wires into the garage from the crawl space… it’s only about 36” long, and there are two copper water tubes running in the same space. And, it’s going to be a little tough to work on from below. (The load bearing block wall is at an angle to the joists.) I was thinking about removing all the dry wall between two studs in that area inside the garage, from the floor to maybe 24” above the floor. Repairing the dry wall and painting is a lot more work that I would like to do. Are there cosmetic panels, or some other way to cover up an opening like that? Is my plan for cutting the dry wall out a good thing to do to make sure I avoid the water tube, and make everything work within that wall space? (I will probably end up mounting the two 110 VAC receptacles on the side of one stud and the 220 VAC receptacle opposite them on the other stud in that same space. The water tubing running in that area bothers me; but, I don’t have much other choice. There’s a PVC waste line that runs in the other wall space, and access from the crawl space is pretty restricted.)

It may be a stange question, but, I was also wondering if it's acceptable practice to have three circuits/receptacle boxes in the same vertical wall space.

Sorry if this is too detailed. I just want to do this right.

Thanks for your help.

Jeff
 
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  #2  
Old 05-13-12, 11:45 AM
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Minor note: Your service is 120/240 volt. Not 110/220v. Make sure your panel is listed to accept tandem breakers.

1) That sounds fine, but there is always a risk of still hitting a wire as you do not know how things were run inside the wall. But with 4" of space, I would expect you will be OK. Only other thing I would like to point out is you will need a connector in the KO you remove from the panel. You may not just run the cable through an open hole.

2) Not sure what to tell you here. Is your garage floor the same level as your house floor? I would suspect not. I would think you could just drill through the rim joist from the inside, avoiding the water lines, and surface mounting a steel box 4x4" to the outside of the drywall. Just come into the back of the box. You could then either install your receptacles there or pipe on the surface with EMT to the location you need.

Pretty much anything goes with receptacle locations. They are placed wherever you need them.

Welcome to the forums!
 
  #3  
Old 05-13-12, 12:41 PM
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Thanks

Hi Tolyn,

Thanks for the reply.

Being an engineer, you would think I would have the 110/120 definition figured out... I'm still confused with some of the products I buy.

Mind if I ask a few more questions?

The connector in the bottom of the panel... is it just a strain relief, or something different? Is it something I will need access to from the bottom, as well as from the inside?

This is a new challenge for me. I used to think that hiring people who are supposed to know what they are doing is the best approach. The electrical contractor who did the wiring in our home is a pretty good example of why that isn't necessarily true. They are a large commercial and residential contractor here in town. One of the two circuits our of the bottom of the panel doesn't even have a strain relief. The other circuit, contracted to them several years after we moved in has a strain relief only. And, in the crawl space the circuit wire was run under the joists (i.e. shortest distance between two points)... it is not run through the joists, or stapled below. They also just have the transformer for the doorbell sitting on the inside of the panel, on the bottom... not mounted to anything. All of the installation waste is still there. (This is the first time I have removed the cover.) Clearly, the quality of their work is inferior to anyone who would do it right.

Your suggestion about the 4 X 4 box is a good one. I was trying to make the installation look as close to original as possible; but, something is going to have to give one way or the other. Will it be acceptable to use the box for 240 and 120, or should I use a separate box for each voltage? Also, the bottom of the rim joist is approximately 3" above the surface of the garage floor. Will the box be okay at that level? Obviously, the receptacle boxes need to be higher. If you were doing this in your own home, is the EMT method what you would go with, or would you conceal the wiring in the wall?

Thanks for your advice.

Jeff
 
  #4  
Old 05-13-12, 02:18 PM
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what I am doing, is adding three circuits into my garage. Two will be 110 VAC (20A), the third will be 220 VAC (40A).
Why not just make one run to the garage with perhaps a 6-3 NM cable with 50 or 60 amp breaker and install a small subpanel?
 
  #5  
Old 05-13-12, 02:22 PM
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Unless "fished" through a finished wall stud space the cables need to be secured to the structure AND by use of a clamp into the circuit breaker enclosure. Sometimes you can install the clamp, less the nut, and fish it through the knockout of the enclosure and then install the lock nut. Most cases it is easier to remove the drywall and patch later.

While it may not be a code requirement in residential garages it is generally considered to be good practice to have any receptacles, or any potential sources of ignition (sparks from a failing splice would be one) a minimum of 18 inches above the garage floor. This MAY be a LOCAL code requirement where you live.

You DID get a permit and are getting an inspection, right?
 
  #6  
Old 05-13-12, 02:55 PM
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The connector in the bottom of the panel... is it just a strain relief, or something different? Is it something I will need access to from the bottom, as well as from the inside?
Not sure what you mean by a strain relief. This is what a connector for Type NM cable looks like. Furd already posted about installing them.

the bottom of the rim joist is approximately 3" above the surface of the garage floor.
It sounds like you can drill up at an angle to make a hole into the stud bay in the garage wall. Then you could cut the openings for your receptacle boxes, push some cable up into the stud bay, and reach into the openings to pull the cable on up.

If you want to know where pipes and wires are in your walls before you drill or cut into them, you can use a stud finder that will locate those in addition to locating framing. The one I use is the MultiScanner® Pro SL from Zircon. I like it, but there are others. Note that the wires in the wall must be energized for the scanner to see them.

Tech note: Your cables should not cross or otherwise contact the pipes in the garage wall. Running next to them is fine.
 
  #7  
Old 05-13-12, 03:03 PM
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Hi Casual Joe,

That was an option we considered. Although the number of wires to the garage would be less, there would still be the same issues.

Thanks

Jeff
 
  #8  
Old 05-13-12, 03:13 PM
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Hi Furd,

To answer your last question first, I did not pull a permit. The last electrical work we had done (adding a 20A circuit/multiple outlets) was done by a licensed electrical contractor, and no permit was done. I also discussed it when buying the breakers with a master electrician at Home Depot. If an inspection is required it will likely cover the deficiencies of the work we contracted. But, I don't want to do something that I'll regret later.

Can you explain what you mean by finished wall stud space? The electrical contractor did not install the clamp and nut. (There is a clamp only located inside of the panel and pointed down through the knock-out, without the nut on the bottom.) I agree with you, installing the clamp and pulling it up into the box probably isn't practical without cutting into the drywall.

Thanks for your advice.

Jeff
 
  #9  
Old 05-13-12, 03:21 PM
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Hi Nashkat1,

The strain relief wasn't the right choice for words. It is actually the clamp portion of the cable type connector. (No nut was installed.)

It is sounding like the surface mounted boxes may be the better choice....

Thanks

Jeff
 
  #10  
Old 05-13-12, 03:50 PM
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A connector serves two purposes.
1) It secures the cable in place
2) It bushes the edge of the hole so it does not damage the cable.

You can fish the connector that Nashkat posted (except much smaller and less expensive) you will just need to cut a bigger hole in the bottom plate. You might have to use a hole saw.
Cutting the drywall might be an easier option and then just install an access panel there for later use. They do sell them at the big box store in the plumbing dept. Or make your own using a pre-made door.

On the other end of the job, yes, it is OK to install a box that low to the floor. As Furd posted it is good practice to to place the receptacles above 18". I like them at 48" myself.
If you are going to put anything on the wall surface, then I would go with EMT. Wiremold is another option, but it is spendy, and IMO does not look any better then EMT that has been painted to match the wall.

You could drill up into the bottom plate and fish the wall cavity between the house and garage, but this will depend on how good your fishing ability is. Drilling the rim joist will likely be much easier.

Lastly, you are likely required to pull a permit. That is all I will say about that.
 
  #11  
Old 05-13-12, 03:51 PM
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Can you explain what you mean by finished wall stud space?
A wall covered with drywall, plaster, paneling or any similar finishing material.

It is sounding like the surface mounted boxes may be the better choice....
That will certainly allow you to place outlets where you want them without having to go through studs. Just remember that all boxes should be at least 18" above the floor, including the first box; you will only be able to make a small hole - about 3/4" diameter - to bring your cables through the wall, unless you want to patch the wall; and you will have to run all of the wiring for additional boxes through protective conduit - preferably EMT.
 
  #12  
Old 05-14-12, 03:25 AM
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Hi Nashkat1,

A wall covered with drywall, plaster, paneling or any similar finishing material.
So with drywall covering the space between the studs, and being required to fish the wire from below, I wouldn't be required to fasten it to the studs?

Just remember that all boxes should be at least 18" above the floor, including the first box; you will only be able to make a small hole - about 3/4" diameter - to bring your cables through the wall, unless you want to patch the wall
The junction box can be lower than 18"? (I understand that anything running from the box must be in EMT.) Can the 240 and the 120 be run into the same box? (I drilled 7/8" holes through the joists, and ran the 8 gauge cable through one set, and the two pair of 12 gauge through the other. I can probably run all three pair through the same 7/8" hole into the garage through the rim joist; but, it will be tight. Is that a good idea?

Thanks everyone for all the great feedback.

Jeff
 
  #13  
Old 05-14-12, 06:51 AM
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When you talked about the large knockout in the bottom I was concerned. The KO should be 1/2" for the smaller cables and 3/4" for the #8. You cannot use the 2" and use one connector for all the cables.
 
  #14  
Old 05-14-12, 07:06 AM
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Hi pcboss,

The original builder's electrical contractor actually ran a single circuit through the 2" hole with no type of connector. I didn't think it was right; but, I didn't know enough to question at the time.

Can I use one connector for the two 120 VAC / 20A circuits?

Thanks

Jeff
 
  #15  
Old 05-14-12, 09:35 AM
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Can I use one connector for the two 120 VAC / 20A circuits?
No. One cable, one connector, one knockout.

You cannot use the 2" and use one connector for all the cables.
But you can use the 2" knockout. You'll need to buy a pair of reducing washers that fit 2" on the outside and the trade size you need on the inside. I think you can get those at the big orange store, but you may have to go to a supply house. I would do that to secure the cable that the worker ran through there without securing it, unless it is smaller than the 8AWG cable you're running for your 240V receptacle. If it is smaller, I would use the reducing washers to drop that hole to 3/4" and open a new 1/2" KO for the existing cable. If you decide not to use the 2" hole for any entry, and to open four new KOs, then you'll need to close that opening with a 2" KO seal.

So with drywall covering the space between the studs, and being required to fish the [cable] from below, I wouldn't be required to fasten it to the studs?
Yes. If you don't remove the drywall, and only cut openings to mount OW boxes for your new receptacles, that's correct.

The junction box can be lower than 18"? (I understand that anything running from the box must be in EMT.) Can the 240 and the 120 be run into the same box? (I drilled 7/8" holes through the joists, and ran the 8 gauge cable through one set, and the two pair of 12 gauge through the other. I can probably run all three pair through the same 7/8" hole into the garage through the rim joist; but, it will be tight. Is that a good idea?
Setting a J-box below 18" in a garage is not a good idea. As Furd posted earlier,
While it may not be a code requirement in residential garages it is generally considered to be good practice to have any receptacles, or any potential sources of ignition (sparks from a failing splice would be one) a minimum of 18 inches above the garage floor. This MAY be a LOCAL code requirement where you live.
If I absolutely had to do that because it was a poured concrete wall, say, then I would set a weatherproof box with a weatherproof cover and run the cable straight through it into EMT connected with a weatherproof (compression) connector. I would not make a splice that low, for the reason Furd noted.

You'll still need a separate connector for each cable here, so you won't be able to fish them all through one hole. You'll need at least two WP boxes if you can find one with two 1/2" KOs in the back for the two 12-2 cables. The other WP box will have to have 3/4" KOs, including one in the back. For safety, I'd use WP connectors for Type NM to secure the cables as the come into the boxes and I'd run a bead of silicone sealer around the back of each box before mounting it to the wall.

BTW, are you familiar with running EMT? Do you have a pipe bender? Can you bend a box offset, for example?
 

Last edited by Nashkat1; 05-14-12 at 10:16 AM. Reason: to correct a typo.
  #16  
Old 05-14-12, 09:48 AM
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The reason behind the 18 inch rule (which IS a requirement in commercial garages) is that gasoline vapors are heavier than air and will sink to the floor level. Keeping any potential source of ignition (spark) above this 18 inch level just plain makes sense.

Of course if you remove the large door so that a garage may no longer accommodate a car you don't need to bother with that particular rule.
 
  #17  
Old 05-14-12, 10:17 AM
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Many NM cable connectors are listed for for use with two cables.
 
  #18  
Old 05-16-12, 09:30 AM
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Some More Follow-Up

Hi Everyone,

Rather than cluttering the thread up by responding to each post individually, I'll cover as much as possible with this one post.

1. Rim Joist: (Sorry that I don't have pictures.) From what I have read, the rim joist sits on a sill plate (2 X 4?) The water piping must actually be installed through the rim joist as it is locate above the sill plate. I am certain I am wrong about the height of the rim joint above the garage floor, although I'm not sure by how much. This may be a stupid question; but, is it possible that there is a sill plate and a rim joist? It appears that the framing may be to the 2 X 4 placed on top of concrete block that forms the perimter of the garage.

2. EMT: No... I don't have experience with a tubing bender for EMT.

3. More Advice: I think I'll head back to where I purchased the breakers and cable and see what I can find in terms of terminal boxes.

Nothing's really easy.... but, at least doing it myself, I'll know it's done right.

Thanks for the advice.

Jeff
 
  #19  
Old 05-16-12, 09:36 AM
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2. EMT: No... I don't have experience with a tubing bender for EMT.
Using pre-bent fitting you can install EMT in most cases without having to bend it.
 
  #20  
Old 05-18-12, 07:50 AM
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Additional Follow-Up

Hey Everyone,

Thanks for all of the advice.

Some of this is becoming more clear.

1. Rim Joist: The two water pipes are installed through the rim joist. I am trying to figure out how I can see how these pipes (copper tubing) are run into the garage wall. From under house (in the crawl space) I can see where the tubes penetrate the rim joist and run horizontally through it. Looking at the garage drywall, there are no pipes coming through the wall, so I am thinking there must be an air gap between the rim joist and the drywall. In that case, it would be different that is shown in the illustration that I have attached. Until I remove the drywall I really don't have any way of knowing. Does this sound like good logic? If so, I am thinking that I will need to see how the pipes get up into the wall space and do something similar with the wiring. Sound logical?
2. Terminal Boxes: I see the logic with the 18" rule. Most of my work involves fire protection in automotive paint shops, and most of our electrical work is specified for Class I Divsion 1 areas. The seal-offs suggested make sense. My question now concerns the terminal box and if it can be installed behind the drywall. I see no way breaking the wire above 18" unless I use a terminal box to pull the wire through. Best case without doing this would result in the wire coming into the garage about 12" above the floor.

All this being said, I am thinking my best approach is to just bit the bullet and pull the drywall in the area in the garage where I plan to install the outlets. That way I'll be able to run all the wiring in the wall space. Then I can install drywall to cover the opening and hope that doesn't mean that I'll need to paint the whole wall.

Maybe I should limit the amount of drywall I cut to run from its bottom edge to about 6" (or maybe 12") above the horizontal 2x4 that runs on top of the floor/rim joist. That would give me enough room to work the wiring through the floor joist and then up into the wall space, and then to the openings for the receptacle boxes. Sound like a good plan? Is there anything I can do to make the drywall repair easier while I'm doing this? (I don't have drywall experience either.)

Are there any types of cosmetic covers I can use for the area where I cut away the drywall?

Thanks for all of your help.

Jeff
 
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  #21  
Old 05-18-12, 08:13 AM
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Drywall Access Panel

Hey Again,

I searched for more drywall repair ideas, and I believe Tolyn Ironhand's suggestion about using an access panel may be the best idea so far. I can get a 15" x 15" access panel which I should be able to locate where I need it so that I can have access to the rim joist penetrations, the 2 x 4 that runs vertically on top of the floor material/rim joist and will give me enough room to feed the cables up to the outlet boxes.

Is there any real downside to this?

Thanks

Jeff
 
  #22  
Old 05-18-12, 05:40 PM
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I see none, but then, it was my suggestion.

About the 18" rule: In residential it is more of a suggestion, then a rule, in the NEC. (some states/cities may require it) Only commercial garages have the requirement. Also, boxes below 18" should be fine and there should not be any arcing there as you might with switches or receptacles.

This might be an opportunity to try your hand at some drywall repair Just cut out a larger piece with a jab saw (at least 12" x 12" enough to get a drill in) and save it for the repair. It would only take some mud, 6" and 12" knife, tape, mud pan, some 1X wood scraps and a sanding sponge. Total investment would be around $50
 
  #23  
Old 05-18-12, 09:26 PM
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I am trying to figure out how I can see how these pipes (copper tubing) are run into the garage wall... Until I remove the drywall I really don't have any way of knowing.
You can do that by using a specialized stud finder. See post #11.

My question now concerns the terminal box and if it can be installed behind the drywall.
No. All electrical boxes must be accessible, whether they contain splices or not.

I see no way breaking the wire above 18" unless I use a terminal box to pull the wire through. Best case without doing this would result in the wire coming into the garage about 12" above the floor.
You should be able to drill from below the house into the stud bays of the garage wall. See post #6.

I am thinking my best approach is to just bite the bullet and pull the drywall in the area in the garage where I plan to install the outlets. That way I'll be able to run all the wiring in the wall space. Then I can install drywall to cover the opening and hope that doesn't mean that I'll need to paint the whole wall.

Maybe I should limit the amount of drywall I cut to run from its bottom edge to about 6" (or maybe 12") above the horizontal 2x4 that runs on top of the floor/rim joist. That would give me enough room to work the wiring through the floor joist and then up into the wall space, and then to the openings for the receptacle boxes. Sound like a good plan?
If you open the wall you will need to secure the wiring per code. See post #5. Even so, that may be the best plan.
 
  #24  
Old 06-10-12, 03:46 AM
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Back to Work

Hi Everyone,

I'm hoping to wrap up the work for the new outlets today. I have been distracted by work, and by other projects.

A quick update... The wiring was run under the house from under the breaker panel to the garage wall. The drywall was cut in the garage to expose an unexpected offset in the copper tubing for the water (not sure it is hot or cold). Two single gang 120 V 20A GFI outlets installed. One 240 V 40A outlet installed. All wiring in the garage secured to studs with insulated staples. Wiring terminated at each outlet. Wiring run from the crawl space into the breaker box through connectors attached to the bottom of the panel (1 connector per cable).

Work left to do... Replace 3 existing breakers with tandem types to accommodate the additional circuits. Rework wiring for 3 existing circuits (to new tandem breakers. Install new 40 A breaker for 240 service. Rework the bottom of the breaker box with reducing washers and connector for improperly wired sump pump wiring. Terminate wiring for new garage circuits.

I hope this isn't a stupid question... but, on the orginal installation the bare copper ground lead for all circuits is attached to the bus on one side of the box. The white lead for each circuit is attached to the bus on the other side of the panel. (An exception is the additional circuit that was added after the house was built... it had both conductors on the same bus.)

Should all bare grounds be wired to one bus, and all white circuit leads be wired to the other bus? Or, does it not make a difference? (Sorry if I'm missing something obvious.)

Thanks for any input.

Jeff
 
  #25  
Old 06-10-12, 06:10 AM
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If the panel is you main/only panel of the house, then the neutrals and grounds may be terminated on the same buss.

If there is another panel, an outside disconnect, or a disconnect on a pole on your property, the neutrals and grounds need to be isolated.

I would suspect that since all the other circuits (other then the "new" one) have them separated, you have a main some place else and this panel is a sub panel. If it is a sub panel, you need to correct the "new" circuit that was installed incorrectly.
 
  #26  
Old 06-10-12, 07:10 AM
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Thanks

Hi Tolyn,

The panel that I'm working in is the only panel at my home. Service from the meter feeds directly into the breakers in this panel (i.e. no outside pole or disconnect). There are no sub-panels connected to this panel either.

It sounds like I should be safe should I wire them to either bus.

I was concerned that there would not be enough bus space; but, after looking more closely there are 3 unused lugs on the bus with all the bare grounds, and 8 unused lugs used for the white lead from each cable. (The lugs on the bare ground side are spread out... I was just considering making it look a little more presentable.)

Thanks

Jeff
 
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