With the arrival of spring, project work on marinas and boatyards picks up, as will Code violations in those places. You’ll find the definition of what those places are in 555.1 of the Code. For NEC purposes, they don’t include private, noncommercial docking facilities used by the owner or residents of the associated single-family dwelling.
Shore enough
Marinas and boatyards don’t have to comply with just Art. 555. They must also comply with Chapter 1 through 4 requirements. This is true for the surrounding facilities, too.
The electrical installations at one marina in West Palm Beach, Fla., looked great at the piers. But it seemed like everything on shore was done wrong, and this problem existed on the long boardwalks to the piers.
Along the boardwalks, none of the ENT raceway was supported between junction boxes [362.30, 300.18]. It sagged so badly that it came apart, exposing conductors. ENT is not permitted in this location due to the constant exposure to sunlight [362.12] unless listed for this use. This ENT wasn’t so listed.
Clearly, the marina owner hired a qualified electrician for the “near the water” work (which complied with Art. 555). But whoever did the work for everything else seemed to be Code-defiant. Two violations in particular were rampant (the requirements aren’t in Art. 555):
• Poor workmanship [110.12]. The boxes and receptacles were at random heights. Raceway was run at varying heights, producing a serpentine appearance.
• Portable cords were cable-tied to the exterior walls of the snack bar and equipment rental buildings [400.8]. Not one was marked with a “W” (listed as Weather/Water resistant); many were just strewn along walkways.
The snack bar opened to a covered “open air” area with tables for those who wanted to dine outside but in the shade. It had lights overhead and receptacles on the railing that surrounded it. Running the raceways on the inside of these rails wasn’t a Code violation (as it would be on, say, the pier). But placing the railing between people and raceways would have made things inherently safer.
Seal the deal
If you install an enclosure on a pier above deck, you must ensure it’s securely and substantially supported by structural members (e.g., don’t use conduit as support) [555.10]. Many enclosures have external mounting “ears” so that you can bolt the enclosure to the structural member without penetrating the enclosure.
But what if your enclosure doesn’t have these features? What if it has just internal mounting holes? Then you must seal the screw heads to prevent water from coming through those holes. Several suitable sealants are available, so pick one — and use it.
One method for ensuring a good seal is to apply sealant to the hole and along the bolt shaft just under the bolt head before inserting the bolt into the hole. As you tighten the bolt, sealant will ooze into the opening and the space behind it. Another advantage is it produces a neater look than what you’d get from squirting goop on the bolt head after assembly.
The “goop on the head” method is a weak way of sealing. The sealant isn’t in the hole and isn’t held in place against pressure by the bolt. This method is also prone to producing thin (or even bald) spots where leaks can occur.
Related
On demand
As with other applications, calculate the general lighting and other loads per Part III of Art. 220. When doing those calculations, don’t apply the demand factor of 220.61(B), unless you specifically are not going to apply the demand factors of Table 555.12.
The demand factor of 220.61(B) is 70% applied to an amount you calculate per 220.61(B)(1) or 220.61(B) (2). That’s a big change. If you’ve got a dozen receptacles and also apply the 80% demand factor of Table 555.12, your calculated load can be seriously off from the actual load.
In this case, your conductors will probably be too small for the load they’ll carry. But the low calculated load means you’ll also undersize your breakers, thus “solving” the undersized conductor problem with chronic nuisance trips.
This kind of mistake is easy to make. First, you perform the calculations per Part III of Art. 220. Then you move on to Art. 550, where there are more demand factors. The thing is, you must choose. It’s best to do that before you start the actual calculations and map out the workflow so you don’t do demand doubly.
Portable power cables
These are mentioned twice in Art. 555 [555.13(A)(2) and 555.13(B)(4)]. What gives? Well, there are some important requirements that you don’t want to overlook.
It seems obvious that a portable power cable used for a marina or boatyard must be listed for wet locations. But don’t overlook the other requirements it must meet. You can use these cables as permanent wiring on the underside of piers and/or where flexibility is necessary (e.g., on piers composed of floating sections) [555.13(A)(2)].
When you use portable power cables (where permitted), make sure they are [555.13(B)(4)]:
• On the underside of the pier.
• Not subject to physical damage.
• Properly supported.
• Securely fastened to structural members (other than deck planking) with nonmetallic clips.
If a portable power cable passes through structural members, use a permanently installed, oversized nonmetallic sleeve to protect it from chafing [555.13(B)(5)]. This chafing prevention requirement is beyond what you’d do when wiring a single-family home, but a single family home doesn’t move up and down. The movement of the pier makes this requirement so important.
Grounding
Forensic reports reveal that many electrocutions near water wouldn’t have happened if proper bonding and grounding had been done. Article 555 starts its bonding and grounding requirements by saying to apply Art. 250 [555.15(A)]. The second requirement is to also apply 555.15(A) through (E).
Other than one specific caution, we won’t summarize Art. 250 in this article. But using Figure 250.1 will help you correctly apply it.
The caution is about the same confusion existing with these installations that exists generally. Installers drive separate ground rods for different systems but fail to bond them. This practice results in dangerous differences of potential. Make sure all of the utility (gas, electric, etc.) ground rods are bonded.
To comply with Art. 250, connect the various ground rods with a suitable bonding jumper installed with listed clamps. If you use a good-sized (e.g., 4 AWG) bare copper solid conductor buried at sufficient depth, it will serve as a good additional grounding electrode while also connecting those ground rods.
Equipment bonding
You must bond metal boxes, metal cabinets, metal enclosures, and metal frames of utilization equipment to an equipment grounding conductor (EGC) run with the circuit conductors in the same raceway, cable, or trench. Also connect the grounding terminals of grounding-type receptacles to the EGC. The EGC can’t be smaller than 12 AWG [555.15(C)].
Article 555 doesn’t require you to bond all metallic objects, but why leave differences of potential? If it’s metallic, bond it.
Avoiding deathtraps
From the fatality data, we see that too many of these facilities have been wired as death traps. While that wasn’t intentional, it was avoidable by complying with Chapters 1 through 4, plus Art. 555. However, don’t stop with mere compliance.
Looking at a job in terms of “what you have to do to pass inspection” leads to corner-cutting. A better approach is to look at how you can keep current flow away from people and the water. Simple things like running the raceway on the “non-people” side of the pier railing are good engineering practices that happen to be a Code requirement.
Lamendola is an electrical consultant located in Merriam, Kan. He can be reached at [email protected].
SIDEBAR: Portable Power Cable Requirements
A portable power cable must be:
• Extra-hard usage.
• Listed for sunlight resistance.
• Rated for wet locations.
• Resistant to temperature extremes, abrasion, oil, gasoline, ozone, acids, and chemicals.
