DiyLightAnimation

Hardware => Lynx Express => Topic started by: Bogususer on December 01, 2009,

Title: Cabling question
Post by: Bogususer on December 01, 2009,
All,

I am in the process of cabling up my yard and am wondering about some of the cabling on my light arches.  I have cut the plug ends off of the minis on each of the 8 channels and have added lengths of SPT2 cord to connect them to the controllers.  Is it a good idea to connect these directly to the LE, or should I think about adding the fused plugs back on for each channel?

Thanks,

Paul
Title: Re: Cabling question
Post by: rrowan on December 01, 2009,
Hi Paul,

For my arches I put the plugs back on to allow easier summer storage and reassembly for next year. If the LE is physically connected to the arches then direct connection should be fine.

Rick R.
Title: Re: Cabling question
Post by: aERonAUtical96 on December 01, 2009,
I thought the fuse in a light string was to help prevent burning out the lights (typical fuse functionality).  If you take that out and have a surge, then your lights take the brunt of the surge vs the fuse.  Just saying that bypassing that, you may burn through lights vs fuses. 
Title: Re: Cabling question
Post by: Bogususer on December 01, 2009,
My concern was more for the LE if something goes wrong on the light end - water, short, etc.  Lights are much cheaper to replace than an LE. 

Paul
Title: Re: Cabling question
Post by: bisquit476 on December 01, 2009,
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My concern was more for the LE if something goes wrong on the light end - water, short, etc.  Lights are much cheaper to replace than an LE. 

Paul

Isn't that the truth!!
Title: Re: Cabling question
Post by: ThaiWay on December 01, 2009,
Of course you'll have to spend a little more by attaching female plugs to plug those retro'd light cord extensions into, but imho the costs (time and expense) and safety would be well worth it.

John
Title: Re: Cabling question
Post by: Murl on December 03, 2009,
Hi Paul,

I nearly left the plugs off of mine, too, but then I started thinking about it and put them back on. 

If I remember correctly, a typical strand of minis draws somewhere around 0.3 - 0.4 amps.  I believe the fuses built into the plugs on mine were 3 amp fuses.  I realized that if I remove the fused plugs and there's a fault of some sort, the next layer of protection would be either the 20 amp fast-acting fuse in the LE or the 15 amp breaker that's feeding the circuit. 

The problem is that I doubt the wire and socket connections on a light string can handle 15-20 amps.  And, if I remember correctly, the LE is rated at 2 amps per channel.  I could see certain types of faults drawing enough current to melt the light string or to damage a channel on my LE without blowing the fuse or tripping the breaker.

Even with the best case scenario and the fuse or the breaker did protect the circuit, now I'd have 16 (or more) channels that go out at the same time, and I'd have to troubleshoot a lot more than a single string.

In my case, I decided it was worth an extra evening to solder the original fused plugs back on.

-Murl
Title: Re: Cabling question
Post by: jjrmace43 on December 03, 2009,
Paul,

The fact your light strings have the fuses in them is half the battle when it comes to troubleshooting and getting your lights back up and running when something is amiss. Also, fuses are there for a reason...to protect the load.

As others have stated, I would take the time to keep the plugs on your lights and install receptacles for ease of connection and troubleshooting...and less cussing...

Just my thoughts.

jjrmace43 
Title: Re: Cabling question
Post by: RJ on December 03, 2009,
The LE is good for 4 amps per channel up to the total controller limit of 40 amps dual power input or 20 amps single power input.

I would recommend leaving the fuses in place. They are there for a very good reason. 

RJ
Title: Re: Cabling question
Post by: mschell on December 08, 2009,
Personally, I think the fuses are there because UL or somebody else said they had to have them to protect someone from sticking a fork in a light socket.

I can't remember if I have EVER had to replace a fuse in one of those plugs on a mini light string.  In fact, some of my rope light strings have those funky plugs and I've never replaced a fuse in them either, and they pull lots more current.

Someone stupid probably hooked up 20 strings and then blew a fuse, or had a fire from overloading the wire in the mini string, and so some regulatory agency decided they needed fuses.

Most of the commercial light strings, and rope light ends do NOT have a fuse.

But to each his own...it's your choice.

Title: Re: Cabling question
Post by: Murl on December 09, 2009,
I didn't do a very good job of explaining this before, but the point I'd like to make is that overcurrent protection is a layered approach, and the fuses really are necessary.

The circuit breaker in your panel is intended to protect the branch circuit - not to protect the equipment that's plugged into it.  For example, if you have a 20 Amp breaker, then the breaker, the wire in the walls, and the receptacle are all sized and rated so they work together as a system so the circuit can handle the rated load and the expected fault currents without catching on fire.

But, the circuit breaker doesn't care whether it's feeding a 20-amp mig welder, or a 0.34 amp string of minis.

That's why you need the fuse in the minis.  The fuse is sized to match the smaller wire and connectors on the string, and limits the current to the range they can safely handle.  Without the fuse, the light string could catch on fire at amperages well below what it takes to trip the breaker.

Please don't take this the wrong way, but... To say you don't need the fuses because you've never replaced one is like saying it's OK to take the seatbelts out of my truck because I've never been in a wreck.

-Murl
Title: Re: Cabling question
Post by: deplanche on December 09, 2009,
Keep in mind that people also can use sets of mini's as an extension cord, and plug in things besides other mini's into the female end.  The fuses keep you from being able to run your electric snowblower from an end of mini's because you don't want to unplug your lights to clear the driveway.

Always have to keep in mind that product design and safety is done for the least intelligence and common sense person in mind... not the typical person you are going to find on this site.  ;D