Notices

URGENT BEWARE OF LED LIGHTING

Old 09-04-2007, 06:11 PM
  #41  
Admirals Club Admiral's Club Member
 
Join Date: Feb 2006
Location: Copiague long island
Posts: 1,228
Default Re: URGENT BEWARE OF LED LIGHTING

personally i would hook it up and do an amp draw test on it ...then determine my fuse or breaker rating accordingly....
ghost28 is offline  
Old 09-04-2007, 06:12 PM
  #42  
Member
 
Join Date: Mar 2007
Location:
Posts: 30
Default RE: URGENT BEWARE OF LED LIGHTING

Hound - 9/4/2007 5:03 PMThat's a pretty small fuse, isn't it? Can I drop that inline, between the boat wiring and the wiring that comes on that fixture?
Yes you could put it inline with that fixture.
Esox1 is offline  
Old 09-04-2007, 08:09 PM
  #43  
Senior MemberCaptains Club Member
Thread Starter
 
Join Date: Jul 2006
Posts: 2,329
Default Re: URGENT BEWARE OF LED LIGHTING

cg states any device containing circuitry shall be fused at its connection to the circuit. leds have circuitry diodes and resistors. therefore should be fused atthe connection to the circuit
hatterasman is offline  
Old 09-04-2007, 09:02 PM
  #44  
Senior MemberCaptains Club Member
 
Join Date: Feb 2002
Location: North Charleston, SC USA
Posts: 22,073
Default Re: URGENT BEWARE OF LED LIGHTING

The idiot who started this thread thinks he is some sort of a marine electrician but he's not (and he's proven it time after time).

If you have an incandescent navigation light, do you select circuit protection for the current draw of the light or do you select circuit protection based on the current capacity of the wiring? (Hint: It's the current capacity of the wiring).

If your navigation light fails internally and burns up, a fuse will not protect it, it will still be toast. Replace it. The circuit protection installed to protect the wiring will still protect the wiring and the boat (house, vehicle, etc.).

Examine the wiring on your boat (and this could apply to your house as well). Do you have a fuse or circuit brealer for each device connected to a circuit? No, you don't. Is there a fuse or circuit breaker for each light? No, there isn't. Why would the fact that the source of illumination is an array of LEDs rather than an incandescent lamp make a difference? It doesn't.

It's great that we have a forum to share ideas and even warnings, but we each need to examine these ideas and warnings to determine if they are valid and come from intelligent and informed sources. Often, as in this case, they do not.
rwidman is offline  
Old 09-04-2007, 09:09 PM
  #45  
Senior MemberCaptains Club Member
 
Join Date: Dec 2006
Posts: 5,612
Default Re: URGENT BEWARE OF LED LIGHTING


I don't think you can name any light source as bad, just as guns don't kill people - lights don't start fires.......... although they may be given opportunity. There are very few wiring jobs I can't find fault with. A strong system IE tight -corrosion free wiring and connections a short like that would open the (fuse) circuit fairly quickly. BUT a system with multiple corroded splices and terminations would have enough inherant resistance to leave ample time to cause damage while waiting around for the fuse (or CB) to heat up enough to open... maybe the real answer there is to verify that there is a CLEAR corrosion-free path across the circuit... with a good meter you should have ~ohms (that's the opposite of a bunch) from each end of each wire (use a jumper silly) you should watch the meter while making and breaking the test, a slight jump of the needle may be cause for concern... I'd really have that checked out! OR do like I did and start rippin' and strippin'!. I frankly wouldn't be caught dead ............with production-style modular wiring I found on my boat! What a mess!

Good Luck
Bill













i
billspen101 is offline  
Old 09-04-2007, 09:39 PM
  #46  
mbb
Senior Member
 
Join Date: Jan 2002
Location: Baton Rouge, Louisiana
Posts: 1,355
Default Re: URGENT BEWARE OF LED LIGHTING

Under the right conditions, a poor connection can melt things and start a fire with ridiculously low current. A fuse based solely on wire rating can permit this, which is why you use a fuse thats only marginally oversized for the device, and always less than the wire is rated for. A blown fuse tells you there is a problem in the circuit, one that wont blow tells you nothing, until theres a fire.

I have personally seen connections melted, and a buddys CC with a fuel tank in the console caught fire in the console from poor connections where the fuse didnt blow. Dont oversize your fuses.



mbb is offline  
Old 09-04-2007, 09:56 PM
  #47  
Senior MemberCaptains Club MemberPLEDGER
 
Join Date: Sep 2004
Posts: 1,047
Default Re: URGENT BEWARE OF LED LIGHTING


This is not as complicated as this thread has made it.. I was a marine electrician and here is the Hull Truth !!

1. LEDs are not the problen !!!

2. No rdwman , you dont leave the fuse the same ! That original fuse was rated for an intirly different "Load" !

You fuse at apprx 150% of normal expected load (wattage) ... because leds are designed for a smaller load and heat dissapation along with any associated wiring or additional electronic devices . the higher resistance of the smaller current carrying surfaces will produce more heat at the same or lower current than the original lights.. You could easily start a fire from the heat generated from three amps flowing through a ckt designed to carry 300 milliamps and the original 10 fuse could care less !!!!

Many people think that because the current draw is small they need not be concerned and do not reduce the fuse and this is the root of the problem.. Remember the heat produced is a function of current and resistance and even if current goes down , if resistence goes up enough you will get more heat at the lower current !!

Bottom line always protect for the load... (the wire is only part of that formula)
whippa4 is offline  
Old 09-04-2007, 10:02 PM
  #48  
Senior Member
 
Join Date: Nov 2004
Location: VA
Posts: 269
Default Re: URGENT BEWARE OF LED LIGHTING

Ron, et al

I had an Ino. combo bow light smoke. No fire, lots of carbon. The itsy-bitsy, tiny-weeny gauge lead wire was toasted by a short inside the potted light. Good thing they were short and not near flamables. If the light had used even 16-18 AWG, it would have popped the fuse/breaker, but they saved 5 cents worth of copper. IMHO, the fine gauge wires are not sufficient mechanically either - mighty fragile. The incandescant Perko that replaced the Ino had slightly heaver wires, but not by much. Before installation, the Perko got modified, replacing the lead wire with #14 marine wire, then sealed and strain relieved.

Woody
Noran - 24 Albemarle Exp
capehaze is offline  
Old 09-05-2007, 09:16 AM
  #49  
Senior Member
 
Join Date: Feb 2007
Location: North Palm Beach, FL
Posts: 8,461
Default Re: URGENT BEWARE OF LED LIGHTING

Weakest link, weakest link, weakest link! Remember this and you will solve a large majority of your problems, whether it is electrical, ground tackle, or life in general. The weakest link burns, breaks or falls apart first.

Applied to LEDs, a properly designed circuit will have as it's weakest link the fuse or breaker. If the fuse or breaker is too large, then the weakest link is the device or the wire. Since the device or wire are not made to open on over-current they will heat up until they open or possibly start a fire (or until the current reaches the capacity of the protective device, which might be too late).

It takes three items of information to properly design a circuit - anticipated load, acceptable voltage drop, and length of wire run. Start with the load. The protection device should be about 150% of the load. Find acceptable voltage drop for device. Measure wire run from battery to device and back to battery. ABYC tables give wire size for length of wire run at load with acceptable voltage drop. Of course, quality products and workmanship ensure a long lasting job.

If you don't know how to do this type of project there are numerous books out there that can give you good info. It's not impossible to learn but you do need to understand what you are doing to safely complete the task. Or you can hire a professional to do the work.
OReely is offline  
Old 09-06-2007, 10:16 AM
  #50  
Senior MemberCaptains Club Member
 
Join Date: Feb 2002
Location: North Charleston, SC USA
Posts: 22,073
Default Re: URGENT BEWARE OF LED LIGHTING

No rdwman , you dont leave the fuse the same ! That original fuse was rated for an intirly different "Load" !

You fuse at apprx 150% of normal expected load (wattage) ...
Let's take a look at the wiring and circuit protection in your house. If it's up to date, you have several branch circuits servicing receptacles in various rooms of the house. They will be wired with #12 wire and protected by circuit breakers rated at 20 amps. Regardless of what (if anything) is plugged into these receptacles and regardless of whether or not they are turned on or off, the circuit protection remains the same. You don’t run out to the garage and swap out a circuit breaker because you've unplugged the toaster and plugged in a lamp instead.

Anyone replaced their incandescent lamps (in their home) with the new high efficiency compact florescent lamps that use one fifth the energy? Did you replace your circuit breakers with five amp circuit breakers?

Let's transfer this logic to our boat. You have one or two 12 volt accessory receptacles. You don't know what will be plugged into them at any given time. You might plug in a map light that draws one fourth of an amp or you might plug in a handheld spotlight that draws ten or fifteen amps. What size circuit protection do you use? Do you change it depending upon what is plugged into the receptacle at a particular time?

Suppose you have five cabin lights on your boat, each with it's own switch and each drawing one amp. They are all on the same circuit. If you follow the advice above, you would use a 7.5 amp circuit breaker if all the lights were turned on at a given time. But what if you only turn one on? Now, according to this same advice, the lamp is grossly under protected because the circuit breaker rating is 7.5 amps and the lamp only draws one amp.

Circuit protection is in place to protect the wiring circuit.

That said, if you install a device having pigtail leads and those leads are smaller than the leads of the circuit, then the device should be protected at the point of connection to protect the pigtail leads. You cannot protect these leads by derating the circuit protection to the entire circuit if the circuit supplies multiple devices.
rwidman is offline  
Old 09-06-2007, 10:34 AM
  #51  
Senior MemberCaptains Club Member
 
Join Date: Jul 2006
Location: So. Fla.
Posts: 372
Default Re: URGENT BEWARE OF LED LIGHTING

rwidman seems correct by logic

In my case, the Cir. Breaker is for the nav lights. I changed the bow light from incandescent to LED but the masthead/anchor light (same circuit breaker) is still incandescent and is sometimes on all by itself. I should fuse where the factory wiring from the LED light meets the wiring that came with the boat. This will protect the wires on the LED light but not the LED itself.
Hound is offline  
Old 09-06-2007, 12:33 PM
  #52  
Senior MemberCaptains Club Member
 
Join Date: Feb 2002
Location: North Charleston, SC USA
Posts: 22,073
Default Re: URGENT BEWARE OF LED LIGHTING

Hound - 9/6/2007 9:34 AM

rwidman seems correct by logic

In my case, the Cir. Breaker is for the nav lights. I changed the bow light from incandescent to LED but the masthead/anchor light (same circuit breaker) is still incandescent and is sometimes on all by itself. I should fuse where the factory wiring from the LED light meets the wiring that came with the boat. This will protect the wires on the LED light but not the LED itself.
You can't protect the LED (the fixture containing the LEDs and circuitry) from itself. If there's a defect or it is damaged, it must be replaced. If you're talking about protecting the light from voltage surges or spikes from the boat wiring, the design of the lamp should account for normal voltage variations.
rwidman is offline  
Old 09-06-2007, 07:45 PM
  #53  
Senior MemberCaptains Club Member
Thread Starter
 
Join Date: Jul 2006
Posts: 2,329
Default Re: URGENT BEWARE OF LED LIGHTING

gee ridman you have done a 180 in your theory from where you started from. i must have enlightened you afterall. since you know tell everyone how many inches of pigtail or leads from a fixture dont count when you are fusing by wire size or load of circuits. how many inches of inferior wire are manufacturers allowed to have for you to connect to the main feeder wires ? and inov lighting uses such cheap glue to hold the lense onto the circuit board, that they may well have used inferior potting epoxy on the boards and just the plain old heat from the resistors burns it up. now hows the consumer protect against that ????? as for me knowing anything about leds and thier use....back in late 80s i built led test light boxes to monitor computer signals on autombile systems. your normal 12volt test light drew too much load and drained the signal from the circuit . so i built led test lights that didnt draw away from the signal yet lit up to tell you when the computer turned solenoids, injectors etc on. the resitors had to be good quality not econo budget versions or they overheated and fried....nowadays you can just walk in and buy those kinds of testers.
hatterasman is offline  
Old 09-06-2007, 09:16 PM
  #54  
Member
 
Join Date: Mar 2007
Location:
Posts: 30
Default Re: URGENT BEWARE OF LED LIGHTING

econo budget resistors?? Who makes those?

Resistors not only have a resistance value in ohms, they have a power rating also. If you're frying resistors it's because you don't know Ohm's/Watt's laws, ignored the power rating, or both. Not because it's an econo budget resistor.
Esox1 is offline  
Old 09-06-2007, 11:08 PM
  #55  
Senior MemberCaptains Club MemberPLEDGER
 
Join Date: Sep 2004
Posts: 1,047
Default Re: URGENT BEWARE OF LED LIGHTING

rwidman... You ever wonder why UL requires some loads that are designed to be plugged into wall ckts to be seperatly fused for thier load and others not? Why does a radio require an internal fuse and a fan not ? Because the ckt breaker will protect the fan but not the radio! this has nothing to do with the house wiring but the device !!!!


The ckt is fused for the known or anticipated load and the wire size is a part of that load but,
should that load be changed from a 5 amp ss load(say fused at 10a) down to a device with internal wiring and devices designed to draw 300 milliamps and an internal failure causes
the device to draw 3 amps.... ever see what 3 amps can do to a ckt board ?


whippa4 is offline  
Old 09-07-2007, 12:41 AM
  #56  
Senior Member
 
Join Date: Sep 2003
Location: Tampa FL
Posts: 4,010
Default Re: URGENT BEWARE OF LED LIGHTING

The simple responce is lower the fuse rating on LED's because in most cases they draw so little they use small wires. So use a small fuse too, otherwise the short continues until the wire burns up, mine have 22 ga wire not the 14 I usually use will 22 burn up with a 14 ga fuse size sure will-hows that

That one company recommended 1/2A fuse so there you go -- don't use 10amp breakers on that circuit simple - stick some small tabs of Duct around the area just to be sure
eggsuckindog is offline  
Old 09-07-2007, 06:47 AM
  #57  
Senior MemberCaptains Club Member
 
Join Date: Aug 2005
Location: Columbia/Pawleys Is. SC
Posts: 214
Default Re: URGENT BEWARE OF LED LIGHTING

Damn!!! My head hurts. Is nothing simple anymore?
waterat is offline  
Old 09-07-2007, 11:33 AM
  #58  
Senior MemberCaptains Club Member
 
Join Date: Jan 2006
Location: Central New Jersey
Posts: 168
Default Re: URGENT BEWARE OF LED LIGHTING

I am so dizzy from doing so many about faces on this subject. Ron, you took the same logic and arguments as I would have done.......even the one about house wiring. Then whippa4 rebutted and won me over to his side. Years ago I had television set that took a surge and shorted something inside. Thank goodness the tv manufacturer had the good sense to have an internal fuse or who knows what might have happened.

So, now I think I would add an inline fuse right before the LED if the main branch circuit breaker feeds other loads as well. Maybe if all my lights were changed over to LED's, I would lower the breaker. I hate adding another point of failure (the inline fuse) because of corrosion issues etc.



Howard
oldrcap is offline  
Old 09-07-2007, 01:56 PM
  #59  
Senior MemberCaptains Club Member
 
Join Date: Feb 2005
Location: Oakland, CA, USA
Posts: 1,450
Default Re: URGENT BEWARE OF LED LIGHTING

whippa4 - 9/4/2007 8:56 PM
Remember the heat produced is a function of current and resistance and even if current goes down , if resistence goes up enough you will get more heat at the lower current !!
Seems to me that if resistance goes up, the current will go down, automagically. Sort of what they call an interdependent relationship there. P=IV; with large values of P being the issue at hand. The problem comes when resistance drops unexpectedly, in ways the circuit is not designed to handle. Then current goes up, and if the fuse is overrated, you run into problems.

If you size the fuse to protect the wiring in te event of a short (i.e. the max current capable of being drawn through the wire in question), you will not have a problem. A complete short will blow the fuse prior to melting the wire. You *may* have problems with the fixture not being able to handle the current without risk of fire, though, so it's safer to fuse for load.

If you size for slightly greater than the normal load, you also won't have a problem. If the device shorts, and the open circuit current increases, the fuse will blow well below the max rating of the wire. Still protected.

The breakers-on-wall-plugs analogy is a bit off-base, as you expect to plug multiple devices into the wall. Since you don't know what the load will be at any given time, you fuse for the wire.

In the boat lighting scenario, you'll have the light on the circuit, but that's it. No varying load (assuming the light works properly), so you are OK to fuse for the load (i.e. an underrated fuse based on wire size.)


jky
jyasaki is offline  
Old 09-07-2007, 05:57 PM
  #60  
mbb
Senior Member
 
Join Date: Jan 2002
Location: Baton Rouge, Louisiana
Posts: 1,355
Default Re: URGENT BEWARE OF LED LIGHTING

Dang it, lets all just use candles from now on!
mbb is offline  

Thread Tools
Search this Thread