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What Constitutes Ignition Protection?
POSTED November 12, 2011
cfr ign protect 2_5718.jpg
I received a query yesterday from a reader asking about a really important issue related to marine electrical system component ratings for ignition protection. I say important because you don’t want your boat to end up looking like the one shown here:
!(http://www.edsboattips.com/images/stories/ignition protection photo_001.jpg)
Doug’s question goes like this:
I would like to know if any classes of products accepted as inherently ignition protected, not in need of testing / a label. Specifically I am wondering about:
– standard sealed inductive proximity sensors
– Brushless permanent magnet sealed motors (no air blowing on windings)
– sealed stepping motors
– Epoxy encapsulated electro-magnets/ electrical clutches
Basically electrical devices that generate NO sparks. Is there any mention of this in the standards
Doug- This question is a tricky one that is a little bit subject to interpretation of the USCG CFR, under Title 33, Section 183.410, Ignition Protection.
Basically there are several statements made within the above referenced regulation that suggest that all of the devices/components you mention are indeed acceptable. I’ve scanned the applicable text right from the official manual:
!(http://www.edsboattips.com/images/stories/cfr ign protect 1.jpg)
!(http://www.edsboattips.com/images/stories/cfr ign protect 2.jpg)
My interpretation of this centers on the statement found next to # 2 above. I believe that the components you are referring to will meet that requirement Doug and are therefore properly separated.
ed’s boat tips
33 CFR 183.410 – Ignition protection.
§ 183.410 – Ignition protection.
(a) Each electrical component must not ignite a propane gas and air mixture that is 4.25 to 5.25 percent propane gas by volume surrounding the electrical component when it is operated at each of its manufacturer rated voltages and current loadings, unless it is isolated from gasoline fuel sources, such as engines, and valves, connections, or other fittings in vent lines, fill lines, distribution lines or on fuel tanks, in accordance with paragraph (b) of this section.
(b) An electrical component is isolated from a gasoline fuel source if:
(1) A bulkhead that meets the requirements of paragraph (c) of this section is between the electrical component and the gasoline fuel source;
(2) The electrical component is:
(i) Lower than the gasoline fuel source and a means is provided to prevent fuel and fuel vapors that may leak from the gasoline fuel source from becoming exposed to the electrical component; or
(ii) Higher than the gasoline fuel source and a deck or other enclosure is between it and the gasoline fuel source; or
(3) The space between the electrical component and the gasoline fuel source is at least two feet and the space is open to the atmosphere.
(c) Each bulkhead required by paragraph (b)(1) of this section must:
(1) Separate the electrical component from the gasoline fuel source and extend both vertically and horizontally the distance of the open space between the fuel source and the ignition source;
(2) Resist a water level that is 12 inches high or one-third of the maximum height of the bulkhead, whichever is less, without seepage of more than one-quarter fluid ounce of fresh water per hour; and
(3) Have no opening located higher than 12 inches or one-third the maximum height of the bulkhead, whichever is less, unless the opening is used for the passage of conductors, piping, ventilation ducts, mechanical equipment, and similar items, or doors, hatches, and access panels, and the maximum annular space around each item or door, hatch or access panel must not be more than one-quarter inch.
AUTHORITY: 46 U.S.C. 4302; Pub. L. 103-206, 107 Stat. 2439; and Department of Homeland Security Delegation No. 0170.1, para. II, (92)(b). Subpart E is also authorized by Pub. L. 114-120, 130 Stat. 27
SOURCE: CGD 72-61R, 37 FR 15782, Aug. 4, 1972, unless otherwise noted.
CITE AS: 33 CFR 183.410