Gas Station Rebuild

[sgunsel]

I have a gas station owner that intends to replace the existing building. The new building will be behind the existing building, which will become parking/sidewalk area. The undergrounds for the pumps, dispensers, etc must be extended to the panel in the new building. Since the 8 or so conduits for underground wiring are mostly under 8 inches of concrete and sealed (hard to replace the existing wires), what is the best way to splice into each of the existing conduits and extend to the new location? Cut conduits and install compression fitting with conduit body on each? What is best way to cut conduit without cutting wires? Thanks.

 

[stickelec]

You can break (bust) the Seals with two hammers, no need to try to cut the conduit. IMO the wire should then be removed and replaced. If the wire cannot be pulled, indicating a possible collapsed conduit(s), then its a perfect time to do a conduit replacement during the remodel.

I suppose an option (economy plan) might be to meg the wire once you have the Seals off and have chipped-away the Chico.

 

[rexowner]

What kind of conduit do you need to cut?

 

[sgunsel]

Rigid metallic.

 

[rexowner]

Rigid metallic.

I'm not sure then. Greenlee 8600 conduit cutter is meant
for EMT, I have used on RNC OK. It is slow even to
cut EMT and requires a clearance of about 6" all around
the pipe. I have never tried it on rRigid, but I would
imagine it would be frustrating and require blade replacement.

Sorry couldn't be of more help.

 

[mdshunk]

Two hammers, one swung with each hand and timed to hit the sealoff fitting on opposite sides at the same time, will smash that sealoff right off in one or two tries. Preserves the threads on the GRC too. Works well for cast LB's and such too.

 

[fishin' electrician]

I have found, almost more often than not, that the sealoffs were either never sealed or that when they were, they were done poorly enough that the conductors slip right through.

One way I've cut RMC with the conductors inside is to carefully score it all the way around as deep as possible, and then snap it in two. Not easy or fun depending on location of pipe but can be done with patience.

Two hammers, one swung with each hand and timed to hit the sealoff fitting on opposite sides at the same time, will smash that sealoff right off in one or two tries. Preserves the threads on the GRC too. Works well for cast LB's and such too.

Wow, I've never heard of this and sure wish I had a year or so ago. Thanks, I will try that next time.

 

[stickelec]

I have found, almost more often than not, that the sealoffs were either never sealed or that when they were, they were done poorly enough that the conductors slip right through.

Those seals would be just great on the side of a NEMA-7 Box with sparking-contacts inside!

BTW, if you ever bust-out a Seal and don't want to disassemble the conduit system, Crouse-Hinds makes a retrofit Seal (Div.2) that is in two pieces and clamps together. See link.

http://www.crouse-hinds.com/catalog/PDFS/00190.pdf

 

[rbalex]

The last time I looked, EYSR seals were not UL listed as required by 501.15(C)(1). The claim of UL compliance has been misleading in the past. Get a UL File Number before you use them.

 

[captaincrab55]

I have a gas station owner that intends to replace the existing building. The new building will be behind the existing building, which will become parking/sidewalk area. The undergrounds for the pumps, dispensers, etc must be extended to the panel in the new building. Since the 8 or so conduits for underground wiring are mostly under 8 inches of concrete and sealed (hard to replace the existing wires), what is the best way to splice into each of the existing conduits and extend to the new location? Cut conduits and install compression fitting with conduit body on each? What is best way to cut conduit without cutting wires? Thanks.

Compression fitting, Very Interesting!... Tell us more about where this compression fitting is going to be used??....

 

[hardworkingstiff]

I have a gas station owner that intends to replace the existing building. The new building will be behind the existing building, which will become parking/sidewalk area. The undergrounds for the pumps, dispensers, etc must be extended to the panel in the new building. Since the 8 or so conduits for underground wiring are mostly under 8 inches of concrete and sealed (hard to replace the existing wires), what is the best way to splice into each of the existing conduits and extend to the new location? Cut conduits and install compression fitting with conduit body on each? What is best way to cut conduit without cutting wires? Thanks.

The best thing to do is to remove the wires at the dispensers and tanks, and pull new conductors after you extend the conduits. Just because something is difficult doesn't mean it's not the best way to proceed.​

If you try to extend existing conductors, you will wind up with a splice that will forever be a source of problems for the fuel electrical system. I believe this will be a disservice to your customer. JMO.​

 

[sgunsel]

Thanks all. Of course there are seals on the other end as well, inside the dispensers, and no way to physically crush those. The accessible seals are above ground, not underground where the conduit needs to be cut and spliced. The owner is concerned about minimal service disruption. I am guessing that the seals are properly installed, at least because that would result in the most work.

Tearing up the concrete to replace the conduit is probably not acceptable.

I have seen compresion fittings for RMC and intended to cut the RMC, install the compression fitting (assuming available with Class I, Div 1 listing) with a conduit body then extend to the new panel with a seal where it emerges above grade. Since there are multiple conduits, all adjacent to each other, I was hoping to find a suitable box to enclose the conduit bodies that would allow future access. Cutting the conduit and having sufficient wire to splice is a big issue since there is not enough room to swing a pipe cutter and a sawzall won't sare the wire.

I will check the seals. If open, it will be easy enough to pull new wires and I agree that would be preferable. The connection method for the conduit would still require to be suitable for Class I, Div 1 since it is underground.

 

[wallyworld]

Two hammers, one swung with each hand and timed to hit the sealoff fitting on opposite sides at the same time, will smash that sealoff right off in one or two tries. Preserves the threads on the GRC too. Works well for cast LB's and such too.

While this can be done, I've done it many times. You can easily squish the pipe and egg shape it while trying to brake the seal off. I use a sawzall if its an EY2 and cut the Y portion(parallel to the pipe) right off. Its allows a bigger opening to the sealing compound and it generally can be removed.

If at all possible I'd pull new wires. If the new store is going to be behind the old one, how do you plan on splicing into the old wires??

 

[rbalex]

There are no compression fittings recognized for Division 1. The NEC expressly requires threaded. See 501.10(A)(1)(a).

 

[petersonra]

is there any reason you can't just extend the conductors and leave what is there alone?

 

[stickelec]

The connection method for the conduit would still require to be suitable for Class I, Div 1 since it is underground.

I've never seen underground classified as Div 1 or 2.

 

[rbalex]

I've never seen underground classified as Div 1 or 2.

Prior to the 2005 you should have seen a Division 1 underground in filling stations. See Figure 514.3 [Edit add: and the text of Section 514.8]in the 2002 or or older editions.
A lot of Article 514 is extracted from NFPA 30A and it oftens reflects the views of a Technical Committe other than CMP14. In 2005, NFPA 30A, Figure 8.3.1 was altered to be more in conformance with CMP14's views.

Article 514 still reflects some unique underground wiring requirements. Primarily because it is the general opinion of the combined NFPA 30A TC and CMP14 that there is sufficent spillage to warrant it.

 

[hardworkingstiff]

Some things you didn't tell us are what the area of the existing conduits will be when the project is finished. Parking? Sidewalk? Landscaping? etc.

That information can determine how you proceed.

The other thing you might not know or be able to determine is what conduit is used underground. It could be PVC. Depending on what you are going to do it may impact your decision.

Where are you intending to install the JB or whatever you are using to splice the conductors? Underground? A freestanding wall?

If you are determined to splice the wiring, and the junction box is going to be under the surface (concrete, asphalt, landscape, etc), then this is a way you could proceed: Start at the trough (an assumption on my part but pretty common) and follow the conduits back to the 1st coupling. Use a side grinder to score the coupling without quite getting to the threads, use mechanical force to finish splitting the coupling w/out damaging the threads. Cut the conduit about 4' from the coupling (towards the trough). Install a horizontal sealoff where you removed the coupling. Install a junction box after the sealoffs. Extend your conduit from there. There should be no additional requirements for sealing. I would NOT recommend this installation.

It really is much easier to just pull in new wire.

 

[wallyworld]

Article 514 still reflects some unique underground wiring requirements. Primarily because it is the general opinion of the combined NFPA 30A TC and CMP14 that there is sufficent spillage to warrant it.

Spillage from what?? Most if not all systems installed now are double wall piping and tanks. They are electrically monitered to pick up the slightest leaks which are contained in the sumps or dbl wall portions of the piping and storage system. Concrete mats line the surface so any spillage can be cleaned up with a customer filling a vehicle.

The reason for all this, cleaning up spills underground is extremely expensive, product that leaves the system without someone paying for it is extremely expensive. I don't see spillage as a major problem anymore not saying it might not happen but it wouldn't be something I would assume to happen???

 

[stickelec]

Prior to the 2005 you should have seen a Division 1 underground in filling stations. See Figure 514.3 [Edit add: and the text of Section 514.8]in the 2002 or or older editions.
A lot of Article 514 is extracted from NFPA 30A and it oftens reflects the views of a Technical Committe other than CMP14. In 2005, NFPA 30A, Figure 8.3.1 was altered to be more in conformance with CMP14's views.

Article 514 still reflects some unique underground wiring requirements. Primarily because it is the general opinion of the combined NFPA 30A TC and CMP14 that there is sufficent spillage to warrant it.

Bob, thanks for the insight. You and others are what makes this site "valuable without measure".

I'm probably missing it but I can't see where 514 classifies the underground, although your comments about spillage makes perfect sense. I know spillage is not uncommon considering those those dummies that go into the store while their vehicle is filling with gas...or sit in the car on the cellphone.