Splicing Romex?

[SteveHGraham]

Thanks for the input. What does "exiting box" mean?

I am thinking I should just cut the romex, put a junction box as high as possible on the wall where I cut the romex, and run three sets of wires out of it: one to the old box, and two to new ones.

I hadn't thought about cutting the cinderblocks to make flush-mount outlets, but I think it would be worth it. Nicer than conduit.

[John Hasler]

>I hadn't thought about cutting the cinderblocks to make flush-mount outlets..

So that isn't what the builder did? What *did* he do, then? You said that the Romex is inside the blocks: how does it get from there to the outlets?

The "exiting box" is the existing outlet where you are going to pick up the circuit. You could simply run Wiremold along the wall from the exiting box.

[SteveHGraham]

I think you misunderstand. I am going to have to cut holes in the concrete, but while I was planning the job, I didn't think about the difficulty of making the holes. I'm wondering what kind of tool they used.

Last time I cut a big hole in concrete, I used an old circular saw with a diamond blade. That won't work on a small box. I'm going to Google around and see what other people do.

[SteveHGraham]

Here's a tool I definitely don't want to pay for.

[spro]

I thought they were flush, didn't expect you would try to do it. We look at garages and shops a different way sometimes. I think the boxes should stand proud and easily accessible. Conduit is great around chest level and some bending involved - but everyone has a bender. I have Romex running around where should be conduit. That was before the mice. I wouldn't insert an electrical box into masonry because its neat.

[choprboy]

When I rewired my house all the outside wall outlets where in block. I cut multiple new holes and fished Romex down the CMUs. It was pretty easy... 4-1/2" angle grinder from HarborFreight. 4-1/2" segmented diamond blade from the same, deep galv metal boxes, and NM cable push-in grommets for the knockouts.

Mark the outline where you want the box in the wall, plunge into the wall with the diamond blade approx 3/16" larger than your mark on each side. Then, depending whether you end up directly in a cavity or straddling a web, knock the piece out with a hammer or cross-cut the center of the knockout. In really difficult cases, break out the hammer drill to drill the corners. If you can see the joint lines its much easier to hit the cavity every time.

Once you have the holes prepared, pull the wires down the wall and out the holes. Place the grommet in the box knockout and pull the wires thru the box, up to the wall. Then push the box into the wall hole and grout in place with hydraulic cement. Hydraulic cement is a bit expensive and you don't need much expansion, so I usually mix it 1:1 or 1:2 with regular masonry grout. Use a work glove and a nice stiff mix and pack around the box. It sets quite fast, usually ~10min later you can use a cold chisel to knock off/scrap off any uneven bits.

[John Hasler]

What he said. Cutting above-grade block is not like cutting concrete.

[SteveHGraham]

This could be an excuse to buy a bottom-tier Harbor Freight grinder. I don't know if it's a great idea to cut masonry with an expensive grinder.

[warmstrong1955]

This could be an excuse to buy a bottom-tier Harbor Freight grinder. I don't know if it's a great idea to cut masonry with an expensive grinder.

Good idea.
I bought one for $7.99 to wire wheel my barbecue so I could repaint it. I didn't want to terrorize my real grinder.
The el cheapo Horror Freight has worn out two wire wheels so far....and it's still going. Has to be at least 15 years old.
It was awful noisy, so I did put some real grease in it. I think the grease they use when they assemble 'em is made out of fish heads & sea slugs.
I bought a second one, for $8.99 a few years later, and put a cut-off blade on it.

[choprboy]

It is absolutely not a great idea to cut concrete/block with a grinder you care about... That said, that HF grinder was amazing, it sucked dust from 100s of cuts, 100+ft of gouging mortar and cracks, went thru half a dozen diamond blades. The bearings growled from all the grit. Finally gave up the ghost after many hours of wire brushing when it got bound up in a corner and burnt a winding.

[SteveHGraham]

I am now up to--I think--three 4.5" grinders. Maybe it's four. I'm planning to get a DeWalt to fill things out. I just ordered a 6" Metabo for cutting metal. I feel like a couple of super-cheap Harbor Freight jobs would be good insurance for those really nasty jobs.

[warmstrong1955]

I'd pass on the DewWalt 4-1/2". Didn't have so many problems with other DeWalt stuff, but the small grinders, are not up to snuff.
I got tired of replacing them for my crew. Had to replace my own too.
Metabo....is a way better tool.