Trouble shooting breaker?

[Eden Lights]

I have my first demon in one of my installs and of course it's driving me crazy. Please share any related experiences that might help? New install with a 15Amp breaker in subpanel going to GFI plug. MDL 600W transformer running about 300W of load 2.6Amps on the primary. While aiming fixtures secondary breaker tripped twice, I checked and confirmed even load on both common lugs. This never happened again, but the 15amp breaker on the primary has tripped three times in the last two weeks. After the second trip the breaker, wiring, and GFI plug was changed. The primary breaker kicked again after two days? Can a faulty transformer be the problem without seeing any reaction from the GFI? Photocell? The client is very understanding, but the performance is no where close to acceptable. The only other thing like this I have had is a transformer that wouldn't run on a GFIC right out of the box and I returned it. It tripped GFIC as soon as being plugged in. Thanks for any information.

[sitelights]

I would change the transformer; if this solves the problem the culprit is obvious. I had an MDL that was shorting out (to the case) from a secondary; I could actually get a voltage reading between the case and a common. Upon examination, a strand of secondary wire on the back side of the lug was touching the case. You might try visually checking for this problem by dropping the front of the case to examine the back side of the connection from the transformer coil to the terminal block. An out of spec GFCI would also be a possibility or a nicked primary neutral but since you have changed these it would seem that the fix is elsewhere. I think you have a fault in the MDL.

[Eden Lights]

I called to order a transformer today to replace the unit on this install and the supplier had some recommendations. The gentlemen asked if the transformer was very close to breaker, which was a definite yes and asked if the breaker was a SquareD which was other yes. He said that other installers were having the same problem and that they were stocking a choke for the primary side, but recommended trying a alternate brand breaker. I have always tried to maintain brands with the box, but I am going to give this a try over the weekend and change the transformer on the next breaker trip. This is not the kind of performance that you want to give your clients, I guess I can smooth this out after I get the problem resolved. We don't have a forum subject for that do we? I was thinking a nice dining gift certificate would get the bad taste out.

[lfalting]

Having worked in the electrical industry for about 20 years, the advise of changing the manufacturer of a breaker in an existing panel will void the manufacturers warranty on the panel. If there is ever any problem with the panel after the change out to a different mfg, you are going to be held responsible. Also if it is a Square D QO panel, no other breaker will interchange.

[Eden Lights]

I looked at this install today. I put a digital amp clamp on the primary and secondary side and cycled the transformer on and off with the timer. I realize that this type of meter is not for looking at spikes, but this is what I saw. 2.5 amps on the primary side and a total of 27 amps on the secondary side while running. While cycling on and off I could get the primary side to spike and trip the fuse I could only see a max of around an 10 amp peak. I was able to repeat this three times in about 50 cycles. Most of the cycles showed about a 4 amp spike. I put the transformer on a 25' extension cord and cycled it 50 times with no problems. I plan to replace the transformer on Monday and recheck.

[Eden Lights]

Replaced the transformer a couple of days ago with a MDL 600SS 12-15V taps. Removed the photocell and reinstalled the wire loop for primary amp readings. Cycled the transformer about 5-7 times using the timer and the breaker tripped and I saw 17amps on the clamp meter, all other cycles showed between 3-4 Amps. I put the transformer back on a extension cord to the outlet. On the way home I was really down on myself because this type of performance is not very becoming of a professional. I have been told the MDL's do this from time to time on this type of primary circuit and the choke is the repair. Choke is supplied from MDL. One part # for 300W transformer and one for 600-900W Transformer. I am worried about future installs of the MDL transformer with the power supply close to the breaker. I have always prefered this install because nothing else is on the circuit and the breaker is outside.

[Eden Lights]

I am interested in others primary wiring specs.

Dedicated circuit for the lighting?

Do you pull off of a circuit in the house?

How are your plugs added?

Duplex off an existing plug?

Add breaker outside in main panel?

Add breaker inside in sub panel?

I quoted a job last year and I had asked the homeowner to have a circuit added. Later I was told that was too expensive the other lighting guy was going to get his power from the door bell. HA HA

[Eden Lights]

I had a call from my transformer supplier today and I was told that MDL has 600 and 900 watt transformers that have been updated for surge protection. Units are ready to ship and MDL is sending call tags for the units that I currently have in stock and the ones installed that have caused my problems. I hope this is the light at the end of the tunnel. Thanks

[Eden Lights]

Well I replaced the problem transformer with a unit that was shipped direct from MDL that I was told has a new update installed to prevent or hide amp spike on transformer startup. The updated unit is much better with average spike of about 3 to 3.5 amps. I still can get a 8-14 amp spike about ever 50 cycles or so. I was told this is causing a known isolated problem on one brand of breaker when the transformer is mounted very close to the breaker location. I have also been told that Hadco, Kichler, Kim, and etc. are all going to this updated style. I would love to hear some tests values on primary draw amounts on transformer startup from some other users??

[par 36]

What you have heard about the other companies having there transformer with changes that you received on your new one is correct, as I had lunch with the owner of MDL last week and that is what he stated. Also, it used to be that you couldn’t install x-10 on transformers larger then 600 watts, it will no longer be the case. You will now be able to go up to 1500-watt units if desired. I for one, have never had the problems that you in countered with amperage spike and have used mainly 900 watt transformers. But have encountered short timer life. I was told that would no longer be the case, as with the changes that they have made, surges to timers and photocell will not be an issue.

[sitelights]

Since you recently had lunch with the owner of MDL perhaps you could provide some insight into MDL's very low profile: no web site, never advertises, not listed in the Thomas Registry, etc. Most, if not all, of the big players in this business have a public presence. Why not MDL?

There are a number of representatives of transformer manufacturers (Intermatic, Q-Tran, Semper Fi, etc) on the Standards Technical Panel (STP) roster for UL1838. MDL is represented on the STP by James Durkin of MDL Corporation's Engineering unit. While I would have expected to see an email address for him @ MDL.com his email is not linked to the MDL Corporation.

Normally I would visit a nearby manufacturer and try to establish a relationship with their technical people especially when I use their product exclusively. MDL's corporate headquarters is in Philadelphia and I am in or near the city on a weekly basis.

I'd appreciate any information you may have and I would especially appreciate a contact person at MDL. Thanks for any help you can provide.

[Eden Lights]

This is from the Hadco website dated this month, I guess better late than never.

LOW VOLTAGE TRANSFORMERS AND INRUSH CURRENT

As a leader in low voltage landscape lighting, Hadco has years of experience with transformers. Recently, we have had instances of house circuit breakers tripping when our low voltage transformers are turned on. Other low voltage transformer manufacturers we spoke with are also experiencing the same issue.

House circuit breakers can trip because of high initial peak inrush current. Inrush current occurs when inductive loads, such as low voltage transformers, are first turned on. Remember years ago when your house lights would dim whenever your refrigerator’s motor first turned on? That was due to inrush current. Inrush current can be many times higher than steady-state current and can, therefore, trip the house circuit breaker.

Hadco has dramatically reduced the potential of circuit breaker trip by installing a surge suppressor in all of our 22 volt HO transformers. In rare cases, the house circuit breaker may still trip depending upon the age of the breaker, total amperage load on the breaker, or total load on the transformer. It is recommended that the circuit breaker be changed to one rated to guard against inrush current, such as Square D’s HOMELINE® HOM-HM high magnetic series, catalog numbers HOM115HM (15 Amp) and HOM120HM (20 Amp), or an equivalent breaker by another reputable manufacturer.

[sitelights]

We are experiencing exactly the problem described; the control transformers are MDL and the "slave" transfomers are Acme Pool & Spa. It is hard to convince a client that the tripping is actually their problem; it is a "client-in-the-middle" circumstance.

As a licensed electrician you can make the retrofit at your cost for time and materials; in our circumstance we have to use an electrical contractor at their rates. This will probably cost at least $150.00; it is worth the expense. Most electricians avoid this "drop in" work because it is simply not worth their time. The problem becomes finding someone to show up; we do expect to pay a premium for prompt response.

We have over $1500.00 in service calls and equipment changes: two new MDL s did not solve the problem. Our service agreements cover all equipment installed by us and our responsibility starts at the existing or provided outdoor receptacle. The cause of the tripping is almost certainly caused by the equipment we installed but the problem began about 2 years ago (on a 12 year old system); we suspect that the problem breaker has gone out of spec.

It is our policy to keep the client out of this type of loop. We would have gladly spent $500.00 for the breaker change out if we had been convinced that the problem was internal. Client good will is a valuable commodity. The system originally cost over $12K. Our three year service agreement price is about 10% of the original cost for 3 year contracts. You win some, you lose some.