PDA

View Full Version : pre wire


zandercorp
04-28-2009, 05:40 AM
I would like to do some pre wire for a future landscape lighting system
could someone tell me if a 900w transformer needs a seperate line from the fusepanel or can the existing outside receptical be used?

Alan B
04-28-2009, 08:26 AM
All low voltage landscape lighting transformers can just be plugged into your outside GFI outlet--no wiring needed from the fuse box. There is not much need for pre wiring other than going under hardscaping (put conduit under walkways, driveways). Unless you have pured concrete and need things like step lights built into the hardscape. The cable itself is fairly easy to install after the fact.

zandercorp
04-28-2009, 08:32 AM
thank you for the help

Pro-Scapes
04-28-2009, 09:07 AM
respectfully I disagree. A 900w trans loaded up can draw 7.5amps or so on the primary. Probably higher on the start up. Simply adding on a 900w trans to a 20a circut may overload it. That will cause more headaches or something later. Imagine everytime you plug in your vaccuum when your lighting is on you have to go reset the breaker or imagine plugging in a hair dryer while you have a light on in the bathroom come to find out the landscape lighting is on the same circuit only to trip the breakers. You MIGHT be ok but if your not its going to be a huge hassel.


If your looking to prewire it would be a no brainer to just drop in a couple of dedicated outlets. You never know what you would like to add in the future. If this was something smaller say 300w and possibly 600 you might be ok but I would at least just place a larger sub panel with free breaker slots near the AC system. You will never once cry about adding in the flexibility.

Other major appliances in your home need a dedicated circuit. Even my microwave has one and it draws 1200 w.

JoeyD
04-28-2009, 11:48 AM
Establishing your power supply is step one. You need to test out that existing outlet and see whats connected to it before determining that it is adequate to power a fully loaded 900w unit. (Like Billy Stated)

It is always best to have a dedicated line from the panel to your transformer but isnt always neccesary. Yes transformers do plug in but some 240v units and even some 120v units get hardwired to the outlet or power supply.

I dont think Gr1ffen fully understood yoru question as far as pullng a new circuit from the panel to power your system. In some cases you may need to have this done. What I usually would do is have the homeowner turn on all the lights and all appliances in the area of that outlet/gfi. I would then use a circut finder to determine which breaker the outlet is controlled by. I would then test the amperage draw and see where we are at usage wise. Depending on how close the transformer is to the panel, you may need to replace the existing breaker with a HACR rated breaker to better withstand the in rush a larger fully loaded unit can produce. They also help when you have other things ont he circuit causing draw.

Spilllight
05-01-2009, 02:29 PM
This is a worthy discussion. The other thing to remember is most utilize existing recepticles for holiday lighting. Sharing the same circuit for landscape lighting would trip the breaker unless the transformer is unplugged during the season.

INTEGRA Bespoke Lighting
05-01-2009, 03:45 PM
Also, with existing outdoor receptacles, you want to know how many are connected to the circuit and ensure they are properly GFI protected and that the GFI is functioning.

Older homes can be a real PITA to find out later that your power source is connected to a switch or other 'crazy' circuit.

I always opt for GFI breakers instead of receptacles when I can as I find the outlets tend to be more prone to false tripping.

Remember the old computer programming saying: Garbage in = garbage out. Same holds true for LV lighting system power sources. I like to have dedicated circuits to all of my transformers when possible.

David Gretzmier
05-02-2009, 12:43 AM
I go overboard further.

since many of my landscape light clients end up christmas light clients and vice versa, I have the electricain do a double outlet, preferable on the outside wall near the panel. most of thier fee is the trip and the time and cost to go from one to two outlets is not too bad. around here most panels are on a an outside wall in the garage or very close. one 20 amp breaker for each outlet. If the panel is full, on newer homes, the A/C unit outside usually has a neutral in the wire, so I have a double outlet with bubble on the side of the a/c shutoff box. they often run heavy breakers and wire on these, 40-60 amp 240volt, but newer A/C units are now 14-19 seer, so they only draw 20-30 amps when starting. lots of breaker and voltage available, 20 amp GFCI outlets. :weightlifter:

and yes, probably 30-40% of the existing outside outlets on homes we do Christmas lights on have the GFCI protection by way of a downstream GFCI outlet in a kitchen, bath, or garage, that already has a toaster, microwaye, hair dryer, curling iron or spare fridge already on it. which your fine as long as nobody toasts bread or curls thier hair while the outside lights are on. :confused:

So the electrician guys like me- easy outlet install and dave pays well for quick outlets. :waving:

Pro-Scapes
05-03-2009, 10:03 PM
I agree totally Dave. Do it right the first time and be done with it. As LED lamps increase in popularity I am guessing we will see alot more pig tailed GFCI outlets where they are simply pigtailed off an interior outlet. Then again we are talking 1-2 amps... no big deal.

One job I had a problem with having the GFCI outlets below the sub panel. The inrush of the MDL 1200w would blow the breaker with a 1050w load on it. This was solved by an external surge suppressor supplied by MDL.

I have tried the GFI breakers with no better luck than a regular GFCI especially when near a subpanel supplying the AC.

On a typical lighting job it costs us between 150 and 400 to obtain adequate power. In rare occasions its higher but it is usually quite reasonable.

JoeyD
05-04-2009, 10:40 AM
I go overboard further.

since many of my landscape light clients end up christmas light clients and vice versa, I have the electricain do a double outlet, preferable on the outside wall near the panel. most of thier fee is the trip and the time and cost to go from one to two outlets is not too bad. around here most panels are on a an outside wall in the garage or very close. one 20 amp breaker for each outlet. If the panel is full, on newer homes, the A/C unit outside usually has a neutral in the wire, so I have a double outlet with bubble on the side of the a/c shutoff box. they often run heavy breakers and wire on these, 40-60 amp 240volt, but newer A/C units are now 14-19 seer, so they only draw 20-30 amps when starting. lots of breaker and voltage available, 20 amp GFCI outlets. :weightlifter:

and yes, probably 30-40% of the existing outside outlets on homes we do Christmas lights on have the GFCI protection by way of a downstream GFCI outlet in a kitchen, bath, or garage, that already has a toaster, microwaye, hair dryer, curling iron or spare fridge already on it. which your fine as long as nobody toasts bread or curls thier hair while the outside lights are on. :confused:

So the electrician guys like me- easy outlet install and dave pays well for quick outlets. :waving:



Those heavy duty breakers are reffered to as HACR (Heating and Air Conditioning, Refrigeration) these are good to use on your dedicated circuits becuase they have a higher tolerance to in rush current.

ccfree
05-04-2009, 09:19 PM
Those heavy duty breakers are reffered to as HACR (Heating and Air Conditioning, Refrigeration) these are good to use on your dedicated circuits becuase they have a higher tolerance to in rush current.

Yes they are Joey. Most standard breakers are rated as 10,000 AIC (amps in rush current). When you have a large transformer (usually a 900w-1200w), within 4 feet to the electrical panel, the breaker in the electrical panel will trip when to system first turns on. Some manufacturers have added a surge protector to their transformers because of this as standard, and some as a add on feature. To combat this problem, if the manufacturer doesn't supply this as a standard feature, simply change out the breaker to a 22,000 AIC breaker and that will fix the problem. It can take the high amp in rush current in that nano-second when the transformer turns on. Some other breaker manufacturers like Square D call it a high magnetic breaker. Just my experience in the field.

David Gretzmier
05-05-2009, 12:11 AM
This is why i am on lawnsite. I knew there were "hevey duty" breakers out there, and now I know what that means. but I never understod, i mean 20 amps is 20 amps. ahh,education.

JoeyD
05-05-2009, 10:28 AM
LOL....and we do use a form of inrush protection in all of our transformers...it is called a Thermister device.....It absorbs the in rush current the transformer can priduce upon firing....but like Craig explained if the units are close tot he panel the Thermister will not always prevent the inrush from tripping the breaker. Thats where a HACR breaker comes in handy...