PDA

View Full Version : In-Line Fusing


emby
05-08-2010, 02:51 PM
Hey guys just wondering about in-line fusing and its applications. If you have multiple zones on one of the commons in the tf is this when you would install them to eliminate the whole common from the tripping? Here is a basic example below. Your expertise and suggestions would be most helpful for an apprentice like myself.
Lets say for example that we have installed four tree lights with 20 watt BABS and these are fed with one feeder from the tf and the wire guage is 12AWG. For symplicity lets say that this feeder is the only one on the first common in the tf.
This would be a total of 80 watts plus lets just say 5 extra for the wire for a total of 85 watts. At 11.5 volts at the hub or T this would be roughly 7.4Amps in total and maybe a little higher due to length of wire.
On the tf the internal breaker is 25Amps is this an example of when you would install an in-line fuse to protect this particular feeder?

Thank you for all your explanations.

Ken

S&MLL
05-08-2010, 06:38 PM
I install my inline fusing at the trans..... (which I rarely do) only really when the lights are in water features. But on a sidenote wouldnt you base the volts off what comes out of the trans. So if its 12 volts then at the trans it would be like 7.2 amps.

But anyway do you install fusing on every homerun? I thought that was something that Unique pushed to contractors. I just dont forsee the need for the extra expense. 20 amp fuse holders are not cheap.

The Lighting Geek
05-08-2010, 08:16 PM
You use a amp probe on the home run and use the next higher fuse.

I used to inline fuse everything and had MANY fuse holder melt due to poor manufacturing, I had 500+ in the field and went back and took them all out.
I used different manufacturers with very little difference. We greased them and still had too many failures. Maybe in the transformer it might be better, but they are problematic in the field.

Pro-Scapes
05-09-2010, 11:28 AM
Since every trans I use has built in secondary protection (ie magnetic breakers) I only use inline fusing when I am running fixtures onto a structure or water feature.

This gives me a little more peace of mind that the clients home is protected should even the smallest short happen. I also do inline fuses for deck lights and arbor mounted lighting.

ELumin8
05-10-2010, 12:07 AM
Guys, consider the purpose of the fuse..To protect. If commons trip, that is an overloading sign. If you are trying to protect the barrier of electricity and water it can only be done with ground fault protection.

If a fuse blows or breaker trips there is usually a very limited reason for it, either a magnetic short has occured, or thermal heating has exceeded the limit.

120/240 volt circuits are protected buy branch circuit breakers that are designed to detect thermal/magnetic occurances down stream. (I only install Square D).

To increase protection on the secondary side of the x-former a simple fuse or breaker system is sufficient. You should never need to add a bunch of fuses if your system is designed and x-formers are sized properly, not to mention it is pain to trouble shoot in the future.

emby
05-17-2010, 10:10 PM
Elumin8,

You have explained my thoughts and concerns. I could not figure out why you would ever have to install the fuse when you have the thermal breaker protecting the circuits.
I guess the question really should have been directed to the manufacturers in asking if the thermal breakers in the transformers are set up to trip during a short circuit situation and an overload situation.
Thanks for all of your thoughts on this subject.

Ken

JoeyD
05-17-2010, 10:33 PM
The only reason you use an inline fuse is to protect the line from a short or overload such as a cut wire or someone replacing a burnt lamp with a larger wattage lamp. If you place an inline fuse at the hub it will only protect the wire from the hub tot he fixture. You then rely upon the primary fuse at the transformer or the secondary breaker/fuse (if you have one) to protect fromt he common tap to the hub.

My advice is to install an inline fuse on every home run on the common side at the transformer. This is time consuming and takes up additional wiring room but now you have properly sized fusing on every single line protecting from the trasformer to the fixture wire.

The problem with common side fuse protection ON the transformer itself is if you have multiple wires connected and one has a problem all the wires get shut down. You then have to figure out which is your problem run. But if you fuse accordingly on every home run then then when a problem occurs the attached fuse will blow signaling which run is the problem run.

good luck!

INTEGRA Bespoke Lighting
05-17-2010, 10:46 PM
Hi Ken. So far reading the responses Joey has it "closest to right" for our systems and requirements here in Ontario. Personally I feel that in-line fusing each and every home run is over kill, but with the new safety regime (read that as red tape machine) running the show here in Ontario you will soon need to pay special attention to those circuits that are powering lights installed on structures.

In order to get the Authorities to back off their proposed requirement that all transformers installed by non-electrical contractors meet Class II requirements, we have suggested that in-line fusing of circuits powering fixtures mounted to structures be a requirement. There is still some hesitation by the Authorities to allow this, as they argue that an in-line fuse is not "tamper proof" therefore would not meet their requirements. (what is 100% tamper proof?)

So that is where we are. It basically comes down to who is inspecting your installations and what are their requirements. Keep in touch with the Landscape Ontario Lighting Group and we will pass along any code or regulation changes as they happen. In the mean time, you might want to get accustomed to reducing your circuits that power fixtures mounted to structures down to no more than 60W runs and installing an in-line fuse... just to be "safe" .

FYI. by structures they are talking about anything built; Decks, Gazebos, shacks, homes, garages, boathouses, docks, trellis', etc.

Regards.

JoeyD
05-17-2010, 11:01 PM
James could this be considered tamper proof inline fusing?

http://i207.photobucket.com/albums/bb97/ulsjoeyd/lighting/IFORCEINSTALL.jpg

http://i207.photobucket.com/albums/bb97/ulsjoeyd/lighting/IFORCEINSTALL2.jpg

INTEGRA Bespoke Lighting
05-17-2010, 11:09 PM
That is a slick installation for sure... but I would bet you some over zealous inspector would flag it for using too many circuit inside the conduit!

Must have been a rather small lot to install so many transformers in the same location. I always prefer to have the TF in the center of the zone.

:) Oh how the home owner would love me... showing up armed with the LED lamps to retrofit into that installation, and making at least a couple of those transformers obsolete! :)

emby
05-17-2010, 11:41 PM
Joey,

Send my congratulations to the installer for that job. I thought I was anal when completing my installations buts thats perfect. The reason I love it is because it is set up just like an electrical distribution center (120V etc.)
I used to build electrical PLC panels way back and that is a prime example of how we use to route and organize all of our wires. Thats art work and obviously someone who really cares about what they do.
Thanks for the info on the fusing (you too James). I can see why it would be a good idea to fuse the individual homeruns especially if you were attaching to combustable strcutures.
Now all you need is some of those Gambino LED tf lights in that trough so you can see what fuse is blown :)

Ken

S&MLL
05-18-2010, 06:03 AM
That is a slick installation for sure... but I would bet you some over zealous inspector would flag it for using too many circuit inside the conduit!

Must have been a rather small lot to install so many transformers in the same location. I always prefer to have the TF in the center of the zone.

:) Oh how the home owner would love me... showing up armed with the LED lamps to retrofit into that installation, and making at least a couple of those transformers obsolete! :)


Its Nates house.

And joey..... 1.Not a big fan of your glue job with all those runs ( plus why did you use quick and wet on gray pvc)

2. All that work..... Why didnt you guys hard wire those trans and use some more conduit. No outlets and would make for a 100 percent clean install.

Pro-Scapes
05-18-2010, 08:04 PM
I agree the power cord job killed that installation.

Tim Ryan does fusing like that. I use the inline marine holders inside the trans and attach them to my run with an Ace connector. Zero issues so far.