CD80 questions

[journeymanjohn]

So, I've been nrowsing info on the CD80 dimmer packs, and have a few questions.

One question is about this "upgrade" control module for them. Am I correct in assuming that this would be for the early ramp card conversions and the AMX. One website I visited was showing a pic of the DMX control module upgrade and it appeared to be saying that it was an upgrade for the "obsolete" DMX, AMX, analog modules. Is this possibly because serveice/repair/replacement of the OEM control modules is nonexistent?? Seems to me, that if it is capable of DMX512, one should be good to go.

Another is about the breaker size on the 24 x 1.2kw modules. Says they are fifteen amp breakers, which as we all know is actually 1.8kw. Ya, it's only 600 watt difference, but still, it would lead me to beleive that either the individual dimmers don't have proper overcurrent protection, unless the dimmers are actually rated for the full 1.8kw or more, and if they are, ...why not just call them 1.8kw dimmers. I would think one could actually overload the dimmers and never trip the breaker till something seriously melts down/shorts or grounds out??

And maintenance and repair issues?? From what I have read, the main problem these dimmer packs face is the replacement of SCRs. Correct?? How expensive is this. Parts?? How bout how difficult is it for one to do themselves.

The particular website was saying most of the electrical issues arise from ground loops and light loops. I am familiar with ground loops, but what the heck is a light loop?? After 20 years in the electrical industry, this is the first I have heard of those.

Thanks all.

 

[Lotos]

One question is about this "upgrade" control module for them. Am I correct in assuming that this would be for the early ramp card conversions and the AMX. One website I visited was showing a pic of the DMX control module upgrade and it appeared to be saying that it was an upgrade for the "obsolete" DMX, AMX, analog modules. Is this possibly because serveice/repair/replacement of the OEM control modules is nonexistent?? Seems to me, that if it is capable of DMX512, one should be good to go.

Yup, if the pack in question has a DMX Control Card in it, you're good to go. If, however, it has an older control module, you're best to replace it. And/Or get a DMX->AMX Converter.

Another is about the breaker size on the 24 x 1.2kw modules. Says they are fifteen amp breakers, which as we all know is actually 1.8kw. Ya, it's only 600 watt difference, but still, it would lead me to beleive that either the individual dimmers don't have proper overcurrent protection, unless the dimmers are actually rated for the full 1.8kw or more, and if they are, ...why not just call them 1.8kw dimmers. I would think one could actually overload the dimmers and never trip the breaker till something seriously melts down/shorts or grounds out??

I don't know about the pack you're looking at, but my 1.2k CD80's have 10Amp breakers on them.

And maintenance and repair issues?? From what I have read, the main problem these dimmer packs face is the replacement of SCRs. Correct?? How expensive is this. Parts?? How bout how difficult is it for one to do themselves.

I have only ever had to send a pack out once, it was a control electronics issue... Technically, I should've just sent out the control card... Live and learn.
As for parts... Philips/Strand officially End-Of-Lifed these units a month or so ago... I have the Memorandum in my Email somewhere if anyone is curious... So parts are going to become scarce eventually... Though as of right now, they're still fixable by just about any shop anywhere.

 

[Footer]

If you have swapped out an SCR before, swapping out a CD80 Pack SCR is pretty strait forward. They are easily accessible in the pack. Just a bit of heatsink compound and you are good to go. I doubt we will ever see the after market stop manufacturing power cubes for these guys.

 

[journeymanjohn]

Thanks guys.

I believe I was reading a pdf manual on the packs, where I read that they were 15 amp breakers. I could be wrong, but wanna say I read it several times trying to figure out the "incorrect" math. I've read so much lately though, maybe it was something else. Been looking at dimmers mainly for the last week or three.

The following CD80 Digital Packs are UL listed and CSA approved:​

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8324 - 24 1.2Kw dimmers (15A primary breaker) with 24 20A Twist Lock
outputs.​

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8325 - 24 1.2Kw dimmers (15A primary breaker) with 24 20A Pin
Connector outputs.​

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8326 - 24 1.2Kw dimmers (15A primary breaker) with 24 20A U-Ground
outputs.​

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8327 - 24 1.2Kw dimmers (15A primary breaker) with terminal strip
connections.​

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​

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8328 - 24 1.2Kw dimmers (15A primary breaker) with 24 15A U-Ground
outputs.​

........................From the PDF file with a strand copyright date of 2006



I have changed out SCRs before, but mainly very large (200A+) ones in large VFDs for large industrial motors. Pretty sure it won't require the same tools. :-D

JJ

 

[journeymanjohn]

Well, I settled on the CD80 as the heart of my system, and my first (and only so far) arrived yesterday.

This one does have 24 x 15amp breakers and has the DMX control module. After further investigation, i found that the Canadian models were built with the 15 amp breakers while the US had 10amp breakers, on the 1.2kw dimmers. It shouldn't be a problem, as I'll be installing four 12gauge soco cables for the outputs so the wiring will be protected (a little overkill never hurt anyone, in regard to wire size), and I'll just make sure not to overload the individual dimmers in my designs. Since these will be used on small stages, it should be pretty easy.

I have not had the opportunity to test it yet, but did open it up to check for archy/sparky marks and such. No burnt smells or such either. Will run it down to one of our local lighting contractors, after xmas, for a full test. Yes, these SCR/SSRs do appear as though they would be an easy replacement. Cross your fingers with me on the control module!!

Thanks for the advice (in the L86 questions thread and here)!! These type of packs are well suited to my needs.

 

[Lotos]

This one does have 24 x 15amp breakers and has the DMX control module. After further investigation, i found that the Canadian models were built with the 15 amp breakers while the US had 10amp breakers

How odd... I would swear *all* the 24x1.2k packs I have contain 10Amp breakers... Though it's possible they're of US Manufacture... I'll have to check now.

I suspect that the 15Amp vs. 10Amp difference has something to do with the Canadian Electrical Code... Which also means that it's possible the pack isn't permitted to be used in the US... You might want to look into that...

 

[journeymanjohn]

They are CE and UL listed, of UK manufacture.

 

[Dionysus]

How odd... I would swear *all* the 24x1.2k packs I have contain 10Amp breakers... Though it's possible they're of US Manufacture... I'll have to check now.

I suspect that the 15Amp vs. 10Amp difference has something to do with the Canadian Electrical Code... Which also means that it's possible the pack isn't permitted to be used in the US... You might want to look into that...

1.2kw/120v=10a

The CEC requires that devices of this nature follow the "80% rule", and thus you need headroom on the rating of the circuit.

This a 12.5a overcurrent device would be required, and since the nearest highest standard breaker is 15amps, they are used instead of 10amp breakers.

There are also other rules that point to the use of a 15a OC device.

Since this question of code has come up several times, I am going to attach some quotes from the CEC, Part I.

Allowable Ampacity for a 14AWG conductor at 60-90 degrees C = 15amps

14-104 The Rating or Setting of overcurrent devices shall not exceed the allowable ampacity of the conductors that they protect except
(a) Where a fuse or circuit breaker having a rating or setting of the same value as the ampacity of the conductor is not available, the ratings or settings given in Table 13 shall be permitted to be used within the maximum value of 600 A;
(b) In the case of equipment wire, flexible cord in sizes Nos. 16, 18, and 20 AWG copper, and tinsel cord, which are considered protected by 15 A overcurrent devices...

Ampacity of conductor 0-15 A , rating or setting permitted = 15A

8-104, Maximum circuit loading
(1) The ampere rating of a consumer's service, feeder, or branch circuit shall be the ampere rating of the overcurrent device protecting the circuit or the ampacity of the conductors, whichever is less.
(2) The calculated load in a circuit shall not exceed the ampere rating of the circuit.
(3) The calculated load in a consumer's service, feeder, or branch circuit shall be considered a continuous load unless it can be shown that in normal operation it will not persist for
(a) a total of more than 1h in any two-hour period if the load does not exceed 225A; or
(b) a total of more than 3 h in any six-hour period if the load exceeds 225 A.
(4) Where a service box, fusible switch, circuit breaker, or panelboard is marked for continuous operation at 100% of the ampere rating of its overcurrent devices, the continuous load as determined from the calculated load shall not exceed
(a) 100% of the rating of the circuit where the ampacity of the conductors is based on Column 2, 3, or 4 of Table 2 or 4; or
(b) 85% of the tating of th circuit where the ampacity of the conductors is based on Column 2, 3, or 4 of Table 1 or 3.
(5) Where a service box, fusible switch, circuit breaker, or panelboard is marked for continuous operationat 80% of the ampere rating of its overcurrent devices, the continuous load as determined from the calculated load shall not exceed
(a) 80% of the rating of the circuit where the ampacity of the conductors is based on Column 2, 3, or 4 of Table 2 or 4; or
(b) 70% of the rating of the circuit where the ampacity of the conductors is based on Column 2, 3, or 4 of Table 1 or 3.
(6) If other derating factors are applied to reduce the conductor ampacity, the conductor size shall be the greater of that so determined of that determined by Subrule (4) or (5).

More than enough reason just there to simply use a 15 amp overcurrent device.

 

[tjrobb]

With the CEC, that may be correct, but NEC allows 100% loading if the breaker can handle it (maybe the CEC allows it as well, I only know the NEC). IIRC CD80's can handle their full load, and even if the breakers are 80% rated the odds of a theatre instrument being on for more than 3 hours is slim.

DISCLAIMER: As stated above I am only versed (and work with) the US codes. I have no experience in areas where the NEC does not have jurisdiction.

 

[journeymanjohn]

With the CEC, that may be correct, but NEC allows 100% loading if the breaker can handle it (maybe the CEC allows it as well, I only know the NEC). IIRC CD80's can handle their full load, and even if the breakers are 80% rated the odds of a theatre instrument being on for more than 3 hours is slim.

DISCLAIMER: As stated above I am only versed (and work with) the US codes. I have no experience in areas where the NEC does not have jurisdiction.

Any chance you could post your code reference for the 100% loading of breakers, and save me alot of time?? Although I am not nearly as proficient in quoting code as I was a ten years ago, it is my understanding that we have the 80% rule too for general branch circuit wiring (exceptions not included). Possibly it is something under the special occupancies section (what is it section 546 or something like that), or maybe something under temporary wiring (which I usually ignore and wire under the standard code whenever they make allowances for less than "standard").

Now that I actually have one of these in hand, and have had the opportunity to inspect it in person, I must say that they seem very well built, and I see little, if anything that would prevent them from being loaded to 15amps ...other than the clearly marked "1200 watt dimmers" posted on the front and nameplate. The internal wiring seems to be #12 if not even #10 (been playing with larger wires lately and it takes a while for me to adjust my feel when goin back to the smaller stuff), but at least #14. Even the SCRs say they are 40amp. There are three smaller wires (#16??) leading down to the control module (which I have NOT removed for inspection yet), but from the quality I see in the rest of the pack, I would be highly surprised to find out these are not fused somewhere.

UL listings are really not that easy to come by, as I understand it, and I doubt that the pack would have one should it had ever come close to causing an electrical/fire hazard, even when loaded to more than 10 amps.

Frankly, now that I have seen the "guts" of the pack, and the quality to which it is wired, I would have to say I prefer these over the ones with 10amp breakers. I would have limited myself to 8 amps on those, and feel quite safe with using the full 10 amps with these. Also, I have formed a habit of running my master fader at 85-90%, which I know is incorrect so far as gel color goes, but I have never had a noticable problem with this.

I am a little concerned about the chokes, in that they seem to be loose within the plastic housing that surrounds them, and these will see some road vibration (typically a show on Friday and Saturday night, then move the rig to another bar/club). My concern is towards maintaining the integrity of the shellac.

Hopefully, the "stage light police" won't show up and shut me down mid show (along with a fine and possibly yanking my license), but I really believe these will be perfectly safe, especially using 12 gauge soco - 15amp breakouts (still haven't made a decision on stagepin, twistlock, or edison). Especially when most of the circuits will only have a few amps on them, and none will have more than 10, although I do have several that will be right at the 10 amp mark. At least I know it will be safer than all those guys who set up with Dollar General extension cords.

 

[mstaylor]

I believe that in lighting equipment you can load to 100%, if allowed by manufacture, because dimmers are air cooled to handle the heat build-up. In a panel set-up there is no air flow so you have to knock the rating down to 80%. I don't know to a certainty to be true but I am fairly certain. Hopefully Steveterry will weigh in and correct me if wrong.

 

[Dionysus]

The CEC also allows for 100% loading, when the overcurrent device is designed for it, I'll paste a copy of the "particular passage" from my earlier post, since you probably did not read it...

(4) Where a service box, fusible switch, circuit breaker, or panelboard is marked for continuous operation at 100% of the ampere rating of its overcurrent devices, the continuous load as determined from the calculated load shall not exceed
(a) 100% of the rating of the circuit where the ampacity of the conductors is based on Column 2, 3, or 4 of Table 2 or 4; or
(b) 85% of the tating of th circuit where the ampacity of the conductors is based on Column 2, 3, or 4 of Table 1 or 3.

 

[derekleffew]

See the thread NEC Code Applicability. It seems to be that if a dimmer is protected by a 15A breaker, it's an 1800W dimmer.

 

[mstaylor]

210.19(A) and 210.20(A) have exceptions for loading circuits at 100%.
I was given this from another electrical board and I don't have a copy of a NEC handy so I'm not sure this is the right exception.

 

[derekleffew]

...and I don't have a copy of a NEC handy so...

As long as one is connected to the Internet, the NEC is at least available, if not handy, at http://www.nfpa.org/freecodes/free_access_document.asp?id=7008SB. Granted the interface is not exactly elegant, but it gets the job done. Not a substitute for owning one's own copy, however.

 

[journeymanjohn]

The CEC also allows for 100% loading, when the overcurrent device is designed for it, I'll paste a copy of the "particular passage" from my earlier post, since you probably did not read it...

Actually, I did read it in the previous post, but as I am in the US...I fall under the jurisdiction of the NEC. Thanks.

 

[STEVETERRY]

See the thread NEC Code Applicability. It seems to be that if a dimmer is protected by a 15A breaker, it's an 1800W dimmer.

Err, not exactly.

The rating of the dimmer is determined by the rating on the NRTL Listing and thus on the equipment label. The breaker rating is not the deciding factor in the dimmer rating.

It would be totally possible to have a 1200W Listed dimmer use a 15A circuit breaker. It would have been tested by the NRTL to prove that loading the dimmer to 15A would not cause overheating or damage that might cause a fire. (The NRTL does not care if the unit stops working, just as long as it stays safe.) Nevertheless, the cooling of the dimmer pack might only deal with 100% loading of all dimmers to 1200W without experiencing thermal shut-downs, so the manufacturer could choose to rate it and have it Listed as a 1200W dimmer that has a 15A breaker.

For another condition, let's say the dimmer was labeled 1800W and had a 15A thermal/magnetic breaker, not a fully magnetic breaker. And further, let's say that it was listed under UL508 (Industrial Control Equipment), rather than as a Theater Switchboard under UL508/UL891. In that case, the 15A breaker would only provide 12A continuous (more than 3 hours), or 1440W.

Bottom line:

1. Read the manufacturer's rating label to get the permissible loading.
2. You need to know if you are using fully magnetic or thermal/magnetic breakers.

ST

 

[STEVETERRY]

Actually, I did read it in the previous post, but as I am in the US...I fall under the jurisdiction of the NEC. Thanks.

Not to hijack this thread, but does anyone else but me wonder about the insanity of having two different electrical codes (NEC and CEC) on two power systems that are connected to a common power grid?

Kinda makes me froth at the mouth when we get into CEC vs. NEC discussions.

ST

 

[journeymanjohn]

Thanks Mr. Terry! U da man!!!

I'll sleep better now, knowing I didn't just blow a wad of cash on dimmers that could be illegal for use in the US!! Knowing this, I'll actually be looking to find 15A breakers on the second one I intend to buy.

These are listed as Industrial Control Equipment, on the label. Will start a google search for a wiring diagram to determine weather or not they are fully magnetic pr therm/mag breakers. Not that I have any intention of loading them to more than the listed rating of 1200 watts, but is good to know ones equipment and it's limitations.

This is my first experience with Canadian vs US code. Kinda reminds me of taking those MSHA (Mining) classes compared to OSHA (occupational) classes. They essentially said the same thing, just worded a bit differently (a few minor exceptions excluded).

Of course, even within the US there are sections of code that don't apply, have not been adopted, or have been modified for various reasons. Where I am located, one would not dream of building a "Service" with PVC, however I understand that some places, Florida I think, PVC is the prefered method. Someone told me it has something to do with either the tornados (or maybe it is ice storms) here or the hurricanes there (I forget which). I understand that in Michigan, residential dwellings are all wired with EMT, where we just run romex here. Different strokes for different folks, I guess.

Thanks all for your contributions!!!!!

 

[Dionysus]

Thanks Mr. Terry! U da man!!!

I'll sleep better now, knowing I didn't just blow a wad of cash on dimmers that could be illegal for use in the US!! Knowing this, I'll actually be looking to find 15A breakers on the second one I intend to buy.

These are listed as Industrial Control Equipment, on the label. Will start a google search for a wiring diagram to determine weather or not they are fully magnetic pr therm/mag breakers. Not that I have any intention of loading them to more than the listed rating of 1200 watts, but is good to know ones equipment and it's limitations.

This is my first experience with Canadian vs US code. Kinda reminds me of taking those MSHA (Mining) classes compared to OSHA (occupational) classes. They essentially said the same thing, just worded a bit differently (a few minor exceptions excluded).

Of course, even within the US there are sections of code that don't apply, have not been adopted, or have been modified for various reasons. Where I am located, one would not dream of building a "Service" with PVC, however I understand that some places, Florida I think, PVC is the prefered method. Someone told me it has something to do with either the tornados (or maybe it is ice storms) here or the hurricanes there (I forget which). I understand that in Michigan, residential dwellings are all wired with EMT, where we just run romex here. Different strokes for different folks, I guess.

Thanks all for your contributions!!!!!

Yes essentially the CEC and NEC are mainly the same. There are few differences. And most of those differences are in wording, or extra/specific differences for one reason or another.

I've commonly built services using PVC (any underground services are PVC here), the only services that are not PVC are "mast" overhead services. Local choices I guess.

Canada does not only have the CEC, but each province has it's own codebook as well (with few differences, none less-than the CEC). And of course everything is up to your inspector anyways.

Are you serious EMT in residences in Michigan? That's NUTS, that would take a LOT longer, and be WAY more expensive. NMD-90 (aka Romex) is the standard residential building wire throughout Canada. However in Commercial applications it is not used (anymore) we prefer AC-90 (aka BX).