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All good discussion..I'd love to eliminate the key on the next go 'round, but there is a fuel fill hose running thru the gauge compartment, so I have to think about it a bit now. 
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-Shawn
"Holiday" - '89 Alura 35 #109
"Twice Around" - '77 C-30, #511 with original A-4 & MMI manifold - SOLD! (no longer a two boat owner!!)
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I don't get/understand how snapping a plastic cover over something like on the 5045 makes it ignition protected. There's still easy air flow over connections. If that's the case, then shouldn't putting a plastic cover over the terminal strip in the picture suffice? And as said above, cover the back of the gauge housing?Originally posted by tac View PostAs Neil implies, your start pushbutton is most likely not ignition protected, and neither are the breakers.
Blue Sea makes 4 circuit (5045), and 8 circuit fuse panels (5046) that ARE ignition protected. They use ATO/ATC fuses.
I appreciate the education
Greg
1975 Alberg 30
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The ignition protection requirement applies to spark producing components such as switches and breakers. A terminal strip does not produce sparks during normal operation. Our starters, distributors, alternators and electric fuel pumps are required to be ignition protected but secure wiring connections are not. Note that this applies to devices in the engine and fuel tank spaces.Last edited by ndutton; 02-20-2018, 10:49 AM.Neil
1977 Catalina 30
San Pedro, California
prior boats 1987 Westsail 32, 1970 Catalina 22
Had my hands in a few othersComment
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Yes, this is why Blue Sea can make an IP device using fuses. The spark producing scenario for an ATO fuse might be if the fuse were to pop out of it’s socket while carrying current, resulting in an arc, followed by a Boom. But the cover fits tight enough over the fuses that it prevents them from popping out. This is why Blue Sea says they are IP only with the cover in place.
Another option might be to use Explosion Proof switches. Companies such as Allen-Bradley (http://ab.rockwellautomation.com/Pus...H-Push-Buttons), Cutler-Hammer, Crouse-Heinie, etc., all make devices for hazardous locations. The prices, and the physical sizes, may cause the Sharp-Intake-of-Breath, but it is a possibility. (For many years I’ve puzzled over why manufacturers of the best industrial electrical equipment have hyphenated names).
For more insight, peruse the USCG regs on this site for a description of IP and the test requirements. Compare that to Explosion Proof requirements in the National Electrical Code (US), or Canadian Electrical Code, and as described in Wicked-Pee-Deah (https://en.wikipedia.org/wiki/Electr...as?wprov=sfti1). After reading all that you’ll probably decide to move your panel.Comment
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For those who’ve slogged through the above references and want more, there is another way out of the fire/explosion threat. It’s not really feasible for small sailboats, but is commonly used, along with Explosion Proof equipment, on tankers, chemical plants, refineries, etc. That is equipment and systems called Intrinsically Safe. See https://en.wikipedia.org/wiki/Intrin...ty?wprov=sfti1Comment
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Checked with Blue Seas yesterday and the pop out CB are ignition proof. If I switch over to contura switches, they too are rated. That along with making sure the locker is properly ventilated would meet the requirements. The locker already has 3 big cutouts into the engine section under the cockpit. Each about 3"x8" - have to go reread that section in the Cdn regs.Greg
1975 Alberg 30
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Switch Ratings
I’m embarrassed that I’d perused the Blue Sea catalog a couple months ago and never noticed that many Blue Sea breakers and the Contura switches (both made by Carling Switch, I believe) are “external ignition protected”, to UL 1500 and ISO 8846. Although there’s no mention of meeting USCG requirements, these two specs would seem to be compatible with them.
Both these specs are available for hire, at a high price. An abstract of UL 1500 can be found at:
The ISO 8846 abstract is even more abstract:
I‘d be concerned about the use of a Contura momentary pushbutton as a start pushbutton. The A4 starter solenoid draws 12 amps. Contura switches are rated at 20A @ 12V DC, or 15A @ 24V DC. This rating is for resistive loads (if ratings do not specify Resistive, Lamp, Motor, or Inductive, it is good engineering practice to assume the worst: resistive load). While this seems satisfactory, the solenoid has a honking big inductance. Switches connected to inductive loads should be rated for at least 3 times the load’s steady state (resistive) rating, or 36A. Otherwise, the arcing across the opening contacts, caused by the inductor’s stored energy that is released on deenergizing the starter solenoid, may result over time in severe switch contact erosion, switch failure, and possibly contact welding. Contura switches do have a 1/2 HP motor rating (1/2HP = 10 amps), which is an inductive rating, but at 125-250vac, not 12VDC.
Carling’s specs for the Contura switches can be found here: http://www.carlingtech.com/sites/def..._datasheet.pdf
Many people use Cole-Hersee switches for starting. C-H, now apparently owned by Littlefuse (a good name in industrial electrical components), used to have the M-612 N.O. pushbutton switch rated at 35ADC, but not ignition protected. C-H was also mum about its inductive rating. Littlefuse has a similar N.O. pushbutton switch, the 9023, rated at 35A at 12VDC and for inductive loads up to 10A (note that this inductive rating is about 1/3 the resistive load rating of 35A). Sadly, it doesn’t appear to be Ignition Protected.
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So with the information from TAC above and the trouble finding a suitable switch to fit this information, it SOUNDS like the best (easiest?) route is to make an enclosure for the switches and a sealed port for the wires to pass through.
I'm thinking of making a little fiberglass box to fit the back of the little aluminum ignition plate in the pic posted earlier, and for the wire port, rubber grommet that can tighten down around the wire to make a seal; two of them - one in and one out.
For completeness I can understand having a cover for the back of the gauge panel, but since there are no switches creating potential sparks is it needed?
This compartment which is about 0.7m^3 has openings at the bottom of the locker of about 3000cm^2 for hoses and the like to enter the engine compartment which is lower down. Any vapour would (should?) sink to the bilge where the blower hose is and would be running?
I am assuming that in the regs below when it says exposed to atmosphere that means directly out of the boat and not into another compartment.
6.3 Ventilation of Spaces Containing Source of Gasoline Vapour
6.3.1 Requirements for Open Spaces
6.3.1.1 Sections 6.3.1.2 to 6.3.1.6 determine spaces that are considered open spaces and do not need to be provided with the natural ventilation system required in section 6.3.2.
6.3.1.2 A separate natural ventilation system is not required if a space containing a source of gasoline vapours, such as a gasoline engine or a fuel tank, has the following characteristics (see Figure 6-2):
at least 0.34 m² (3.5 ft²) of area exposed to the atmosphere per cubic metre (35 ft³) of net space volume; and
no long or narrow unvented spaces in which a flame front might propagate.
6.3.1.3 The net space volume is the volume of space containing the source of gasoline vapour plus the volume of connecting spaces, unless the connecting spaces either:
connect to spaces already ventilated by ducting; or
themselves qualify as open spaces.
6.3.1.4 Spaces connecting with spaces open to the atmosphere, which have interconnecting openings with an area equal to 2% or less of the separation bulkhead, are not considered as open spaces.
6.3.1.5 The separation bulkhead area used for the calculations in paragraph 6.3.1.4 and 6.3.3.3 is calculated using a height that is the lesser of either the distance between the bottom and top of the bulkhead between the spaces, or 750 mm (30 in).
6.3.1.6 Long narrow spaces with a length to width ratio greater than 1:5 formed by side panels or under accommodation decks shall have openings at both ends or along the sides in order to qualify as open spaces.
Figure 6-2. CHARACTERISTICS OF OPEN SPACES
6.3.2 Natural Ventilation of Enclosed Spaces
6.3.2.1 A separate natural ventilation system is required for any enclosed space that does not meet the requirements for an open space as set out in section 6.3.1 and that contains one of the following sources of gasoline vapour:
a permanently installed gasoline engine;
a portable gasoline fuel tank that ventilates into the space; or
a non-metallic gasoline tank:
with an aggregate permeability rate exceeding 42 grams of fuel1 loss in 24 hours per cubic centimetre (1.2 grams per cubic foot) of net compartment volume; or
with a net compartment volume of less than 0.028 cubic metres (1 cubic foot), having a permeability rate exceeding 1.2 grams of fuel loss in 24 hours.Greg
1975 Alberg 30
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Another option is to use a Contura momentary normally open (N.O.) pushbutton to operate a power relay that works the starter solenoid. Advantages:
1. The relay coil draws less than an amp, well within the Contura specs.
2. The relay can be located anywhere that ignition protection is not required.
3. The Contura is ignition protected.
4. No cover will be needed on your panel if all other components are ignition protected.
5. Connection atween the PB and the relay coil can be as small as #16 wires.
6. Add an LED and resistor across the relay coil, or better, across another set of contacts, to give visual indication that the relay is energized. That LED could be mounted on the panel, or on the relay.
7. Add a reversed biased diode, like a 1N4005, for transient protection. The diode, LED and 1KΩ resistor are available from Digikey. One stop shopping.
Potter & Brumfield (formerly a hyphenated Potter-Brumfield) is a maker of some of the best MIL-SPEC relays that can be found in the universe. I see (sadly) they’ve been bought out by Tyco. These relays are automotive, not MIL-SPEC, found through Digikey:
I would use the $12+ relay. The four pages of specifications makes my heart beat faster. The blades can be easily wired using insulated 1/4” female terminals. Mount the relay on it’s side with a glop of silly-cone or super glue. Or buy a socket.
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Disadvantages:
every connection and component are potential failure points. That is the concern/trade-off I've had with the ballast resistor solution for electronic ignition, one additional connection and one additional component in the circuit.Neil
1977 Catalina 30
San Pedro, California
prior boats 1987 Westsail 32, 1970 Catalina 22
Had my hands in a few othersComment
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Probably Off Topic
Neil:
I wholly agree with your concern over complexity and it’s attendant effect on reliability. But sometimes there’s the inevitable tradeoff - in this case added complexity vs. safety and regulations. You and I are quite comfortable with installing, testing, diagnosing and fixing mechanical, and especially electrical, systems. My first thought on dealing with the ignition protection requirements of the OP’s setup was a relay, but I held back because of the added complexity. Not knowing the OPs electrical knowledge was also a large factor.
However, the many reports of ignition keyswitch and pushbutton failures only reinforces my belief that the common boat 10 amp rated switch in a starter solenoid circuit is asking for trouble. Few people, including some electrical engineers I’ve known, know switches are rated for resistive, inductive, lamp, or motor loads, and why the different ratings. Unfortunately, only the best manufacturers publish this data.
I don’t believe, in general, adding a relay increases complexity and decreases reliability significantly IF AND ONLY IF:
1. Material is chosen correctly and knowledgeably
2. The installation (location of components, mounting, wiring runs, terminations, labeling, etc) is done in accordance with best practices.
But that applies to everything, doesn’t it?Comment
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Start Circuit Relay
If you decide to go with a relay in the start circuit, the attached drawing shows one way to do it.
CAVEATS:
1. This is a schematic (it shows how the circuit works).
2. It is NOT a wiring diagram, which would show the actual point-to-point wiring.
3. No protective devices (fuses/breakers) are shown. Remember when adding fuses/breakers: you’re protecting the smallest wire in that leg, not the devices.
4. Wire sizes are not shown. The pushbutton/relay coil circuit will draw less than .2A, so a #14 will do. The circuit with the relay contacts and starter solenoid will draw 12A, so a #10 or #12 might be used, depending on length.
Suggested parts:
1. Blue Sea Contura normally open momentary pushbutton, like the 7930. Or any other ignition protected N.O. momentary pushbutton.
2. If you add the optional LED, the Blue Sea 8172 is rated at 12/24VDC, has an integral resistor, is easily panel mounted, and is generally under $4. The LED is shown connected so it lights up when the relay’s normally open contacts are closed.
3. The relay. The TE Connectivity 3-1393303-4 is a normally open 12VDC relay which can handle 60A loads. It is designed for automotive service. Terminations are by 1/4” female push-on terminals. The relay has an integral mounting bracket. Digikey part no. A122266-ND. Only $9.61.
The relay data sheet (all 4 pages) is here:
4. If you add a transient suppression diode across the relay coil (and you should), Digikey will let you have a 1N4005 (Digikey part no. 1N4005-E3/54) for $.23
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Waiting for some coloured wire to come in so can finish. Found that a Grp27 battery box cut down will fit perfectly behind cockpit opening- going to either epoxy or 5200 it in place. The multiple wires running through the vapour glands will also be filled with sealant to plug the little gaps between the wires. And to add wire labels. Wire tidying will happen once installed.
Greg
1975 Alberg 30
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Very NICE!Neil
1977 Catalina 30
San Pedro, California
prior boats 1987 Westsail 32, 1970 Catalina 22
Had my hands in a few othersComment
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Maybe not specifically applicable to this installation, but I've used these:
Cut the back out leaving a lip that can be used to seal against a bulkhead. Cable glands for entry. And you have the benefit that if you need access to the wiring then you can remove the gasketed lid.
By the way, there are lots of spots on our boats that potentially can get overlooked when it comes to ignition protection, especially with the smaller boats that the A4 was so common .... fuel tank, engine, batteries, DC systems, AC systems ... all 'piled' on top of each other in one big open, interconnected space.
Heck in my C&C 27 ... and just about all C&C models up to the early 80s ... the DC circuit breaker panel is mounted right above the fuel tank (and right behind the sink for that matter). Can't be a good idea!
For example, the fuses that are supposed to be installed in the ignition / starter systems. Is the 60-amp ATC inline fuse holder sold here at Moyer ignition protected? I don't think so.
What about that auto charge relay for our house bank ... ever-so-popular Echocharger? Not ignition protected!1979 C&C 27 MkIII, Hull No. 780
Cygnet
North Saanich, BCComment
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