Cathodic Protection System for above ground fuel storage tanks

[fbhwt]

Has anyone here installed Cathodic Protection Systems in locations such as above ground fuel (gasoline, diesel, JP-8) storage tanks? I have come across a system that is installed in an area surrounded by 20,000gal tanks and above and below ground piping. There is a 2 pole 60 amp outdoor rated disconnect feeding a rectifier, neither enclosure is class 1 rated.

 

[rbalex]

I've designed several, both impressed current and sacrificial anode types.

Something to consider with tank farms is that much of the equipment on dikes is actually outside of classified locations. Bonding inside classified locations is still important. Boundary seals may need attention.

Make sure that the classified locations are accurately documented.

 

[fbhwt]

I've designed several, both impressed current and sacrificial anode types.

Something to consider with tank farms is that much of the equipment on dikes is actually outside of classified locations. Bonding inside classified locations is still important. Boundary seals may need attention.

Make sure that the classified locations are accurately documented.

Thanks, I'm in the process of gathering information, there are containment dikes around the tanks, this rectifier is in the middle surrounded by 25,000 and 75,000gal tanks, small fuel farm.

 

[fbhwt]

Pictures

Pictures

Thanks, I'm in the process of gathering information, there are containment dikes around the tanks, this rectifier is in the middle surrounded by 25,000 and 75,000gal tanks, small fuel farm.

Pictures showing cathodic protection, disconnect with explosion proof flexible conduit and above ground fuel tanks.

 

[rbalex]

I can't quite tell from the photographs but you may be out of the classified envelope by distance from the tanks alone.

Technically, there is no "explosionproof flexible conduit ";it is an explosionproof flexible coupling. [See Section 501.10(A)(2)(1)] The distinction is the connectors are factory assembled and integral with the raceway. If the installation is in a Division 2 or unclassified location, it is likely to be a waste of money. Those fittings aren't called "golden rope" for nothing.

 

[fbhwt]

I can't quite tell from the photographs but you may be out of the classified envelope by distance from the tanks alone.

Technically, there is no "explosionproof flexible conduit ";it is an explosionproof flexible coupling. [See Section 501.10(A)(2)(1)] The distinction is the connectors are factory assembled and integral with the raceway. If the installation is in a Division 2 or unclassified location, it is likely to be a waste of money. Those fittings aren't called "golden rope" for nothing.

See section 501.10(B)(2)(2) It says: Flexible metal conduit with listed fittings. Though this rectifier is outside the dike, it is inside an area with piping used for transferring fuel from the tanker to the storage tank. I see table 513.3 references inside the dike, trying to find out what the classification is in this area.

 

[rbalex]

Section 501.10(B)(2)(2) is referring to FMC [Art 348]. It isn't explosionproof. Nothing in Section 501.10(B)(2) is explosionproof it isn't necessary in Division 2.

Article 513 doesn't apply to your installation; I suspect you meant Article 515. Did you check Table 515.3? NFPA 497 and API RP500 both have appropriate diagrams. Inside the dike is likely to be Division 2. Outside is likely unclassified.

 

[fbhwt]

Section 501.10(B)(2)(2) is referring to FMC [Art 348]. It isn't explosionproof. Nothing in Section 501.10(B)(2) is explosionproof it isn't necessary in Division 2.

Article 513 doesn't apply to your installation; I suspect you meant Article 515. Did you check Table 515.3? NFPA 497 and API RP500 both have appropriate diagrams. Inside the dike is likely to be Division 2. Outside is likely unclassified.

rbalex, I do not doubt your expertise in this area, so please do not be offended, I am just trying to understand. Article 501= Class I Locations, Article 500.5 Classification of locations, 500.5(B) Class I Locations, would that not require explosion proof equipment/material?

 

[fbhwt]

Section 501.10(B)(2)(2) is referring to FMC [Art 348]. It isn't explosionproof. Nothing in Section 501.10(B)(2) is explosionproof it isn't necessary in Division 2.

Article 513 doesn't apply to your installation; I suspect you meant Article 515. Did you check Table 515.3? NFPA 497 and API RP500 both have appropriate diagrams. Inside the dike is likely to be Division 2. Outside is likely unclassified.

Yes you are right, I meant 515.3, like I said I'm just starting to research this, took me a while to learn how to drive a stick, didn't jump right out on the race track.

 

[rbalex]

rbalex, I do not doubt your expertise in this area, so please do not be offended, I am just trying to understand. Article 501= Class I Locations, Article 500.5 Classification of locations, 500.5(B) Class I Locations, would that not require explosion proof equipment/material?

I overgeneralized the case a bit; explosionproof equipment may be required in Division 2 if the equipment is arcing, sparking or high temperature(ASH) in normal operation like switches, luminaires or heaters. However, explosionproof wiring methods are rarely required in Division 2. The limited cases are mentioned in Section 501.10(B)(4).

If Class I automatically required explosionproof equipment, there is very little reason to even distinguish between Division 1 and 2.

Dealing with classified locations is typically a two-part process. First, the electrical area classification must be determined. Second, the proper equipment must be selected. Your installation is one of the few that classification can be directly determined from the NEC itself. [Art 515]