classified area at marina

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hardworkingstiff

Senior Member
Location
Wilmington, NC
I am curious as to the opinions of where the classified location is when you put a long hose on a gas dispenser at a marina.

NFPA 70 does not address this. It simply states 20' from the dispenser to a height of 18". The local (inspection department) viewpoint is the classified location extends to 20' from the end of the hose. I don't agree with this, but do agree that with a longer hose the classified location should be extended.

Comments please.
 

rbalex

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Staff member
Location
Mission Viejo, CA
Occupation
Professional Electrical Engineer
Re: classified area at marina

Originally posted by hardworkingstiff:
I am curious as to the opinions of where the classified location is when you put a long hose on a gas dispenser at a marina.

NFPA 70 does not address this. It simply states 20' from the dispenser to a height of 18". ...
NFPA 70 does address this; Article 555 sends you back to Article 514 which specifies the dimensions you cited.
Originally posted by hardworkingstiff:
...The local (inspection department) viewpoint is the classified location extends to 20' from the end of the hose. I don't agree with this, but do agree that with a longer hose the classified location should be extended.
Why?
 

hardworkingstiff

Senior Member
Location
Wilmington, NC
Re: classified area at marina

Bob,

At a land based fueling facility, the hose is typically no more than 12' long. At one time the NFPA 30A limited a hose length to 20'. A car could easily be 10' from the dispenser when fueling (thereby being only 10' from the end of the classified area). When you put a 50' or 100' hose on a dispenser at a marina you can fuel a boat well out of the 20' classified area (514) and vapors will be present during fueling operation.

A vent opening from a tank is classified Class 1 Division 1 to a radius of 5' and Divison 2 to a radius of 10'.

I believe the NEC has left an area of concern when it referenced 514 for marinas. The longer hoses can create pocketed areas that should be classified during fueling.

Dock space is expensive, so I do not like the idea of enforcing 20' from the hose, but I like to look at the vent classification for guidance.

Bob, the short time I've been reviewing these boards, I've come to admire your comments. I wonder if you would also comment on the following opinion. If a floating dock has a gas dispenser on it and type W cable passes through the area of the dispenser (within 20? of the dispenser and less than 18? above the water) with no splices, no seals (as in sealoffs) are necessary.
 

rbalex

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Staff member
Location
Mission Viejo, CA
Occupation
Professional Electrical Engineer
Re: classified area at marina

You have stumbled upon one of the more interesting questions going on in electrical area classification debates: Does electrical area classification apply to locations where there are no ignition sources covered by the NEC? There are fairly strong arguments on both sides. One side will say that area classification is simply determined by the ?geometry? of the potential fuel sources regardless of ignition sources. The other side says the Scope of the NEC limits it to installations ; [90.2(A)] it is electrical area classification and, if there are no ignition sources covered by the NEC, there is no reason to classify the area.

For example automobiles, except parts of motor homes, are generally exempt from the NEC yet they drive through Division 2 locations literally millions of times a day. More significantly, the hose nozzle is usually well above 18? yet there is no indication in Art 514 that there should be a ?roving? fuel source above 18?.

The closest thing to a recognized ?mobile? fuel source is shown is Figure 515.3 . (Bulk Storage) In this case the source may move but the electrical area classification is still fixed.

The general resolution to the original question is that the electrical area classification definitely applies to permanent installations but ?mobile? operations may be reviewed, case-by-case. The incidental ?spill? at a hose nozzle usually does not warrant electrical area classification. The dispenser is different; under ?abnormal? conditions a small leak could produce a persistent fuel source; therefore it is the judgment of the TC/CMPs that Figure 514.3 is necessary and sufficient to define the boundaries.

With regard to your second question: ?Type W? is permitted as a Division 2 wiring method where the application is consistent with Section 501.4(B)(2). In general, listed cables with undamaged jackets are permitted to pass completely through Division 2 locations with no additional seals per 501.5(E)(3) Exception. Note: Section 501.5(E)(4) applies to cables with interlocked armor sheaths or damaged jackets.

Thank you for your very vote of confidence :D
 

Rockyd

Senior Member
Location
Nevada
Occupation
Retired after 40 years as an electrician.
Re: classified area at marina

May want to seek answers from other "code sources" such as API (American Petroleum Institute) or a manufacturing representative of such equipment like Veeter Root (they make metering for fuel dispensers).
 
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