The runway and taxiway lights at airports are operated on a 6.6amp constant current series circuit with a #8 conductor with 5kv insulation. LED lighting is coming to this industry. We now have the opportunity to use lower current and voltages. Since airport lighting cables often run together in the electical vault or field home circuits I assume any new low voltage circuits for LED lighting will have to maintain 5kv insulation if in proximity with other 5kv cables that are still using the higher voltages? If all the 5kv cables are still being used but now they carry a maximum of 600 volts due to LED lights now being used on all circuits can new cables that are added be just 600 volt rated? Will be glad to clarify if the issues not clear.
Airport Lighting Series Circuit
- Thread starter sewardf
- Start date
- Status
- Location
- Bremerton, Washington
- Occupation
- Master Electrician
Re: Airport Lighting Series Circuit
It depends on what type circuit the LED system uses. The circuit types are defined in Art 725. Keep in mind you can have a "low voltage" circuit that is not power limited, ie high amperage, and in that case it becomes an Chapter 3 installation.
It depends on what type circuit the LED system uses. The circuit types are defined in Art 725. Keep in mind you can have a "low voltage" circuit that is not power limited, ie high amperage, and in that case it becomes an Chapter 3 installation.
flightline
Senior Member
Re: Airport Lighting Series Circuit
You seem to be under a mis-understanding. The NEC does not dictate wiring on FAA airfields. The documents you must go by are FAA Advisory Circulars. I work at one of the bigger and busier airports. We have both 6.6 amp CC circuits as well as 20 amp circutis for the majority of our high intensity runway circuits. Some of our runs between the lighting vault and the begining of the runway circuit itself are over 2 miles. We use a #6 LA24 FAA 5kV Type "C" airfield lighting cable.
There has been a huge proliferation in LED fixtures, however, I am of the opinion that they will keep the 5kV level. The load isn't that too different, and you must remember that everywhere there is an airport, there is this installed base of circuitry & regulators. The airfield lighting transformer local to the fixture, marker light, or guidance sign will probably remain. Lets face it; from start to finish there are some circuits that are miles long, and 480 just won't cut it. These fixtures must be able to be operated at the different levels of intensity as desired by weather conditions and the ATC tower. Perhaps a still-to be-built, brand new, smaller to mid size airport may be able to utilize the technology as you indicate, but in the mean time, a great deal must change. I know the LED airfield lighting manufacturers now are seeking to integrate their equipment into existing infrastrure and reap the interim benefits.
You seem to be under a mis-understanding. The NEC does not dictate wiring on FAA airfields. The documents you must go by are FAA Advisory Circulars. I work at one of the bigger and busier airports. We have both 6.6 amp CC circuits as well as 20 amp circutis for the majority of our high intensity runway circuits. Some of our runs between the lighting vault and the begining of the runway circuit itself are over 2 miles. We use a #6 LA24 FAA 5kV Type "C" airfield lighting cable.
There has been a huge proliferation in LED fixtures, however, I am of the opinion that they will keep the 5kV level. The load isn't that too different, and you must remember that everywhere there is an airport, there is this installed base of circuitry & regulators. The airfield lighting transformer local to the fixture, marker light, or guidance sign will probably remain. Lets face it; from start to finish there are some circuits that are miles long, and 480 just won't cut it. These fixtures must be able to be operated at the different levels of intensity as desired by weather conditions and the ATC tower. Perhaps a still-to be-built, brand new, smaller to mid size airport may be able to utilize the technology as you indicate, but in the mean time, a great deal must change. I know the LED airfield lighting manufacturers now are seeking to integrate their equipment into existing infrastrure and reap the interim benefits.
- Location
- Bremerton, Washington
- Occupation
- Master Electrician
Re: Airport Lighting Series Circuit
I was orginally going to post that airport runway lighting does fall under the scope of the NEC, per 90.2 it does. But it may be an FAA issue for some airports, but many airports are not federal installations but county, state or port authority.
I was orginally going to post that airport runway lighting does fall under the scope of the NEC, per 90.2 it does. But it may be an FAA issue for some airports, but many airports are not federal installations but county, state or port authority.
charlie
Senior Member
- Location
- Indianapolis
Re: Airport Lighting Series Circuit
The only thing I know about it is that the open circuit voltage of a 6.6 A constant current regulator is treated as 5 kV class for construction. The circuits are very dangerous because a second ground fault is just a lesser amount of load and is adjusted for by the regulator. We used a lot of IL transformers to get 90 volts and then changed to MV lights with IL transformers.
We have finally gotten rid of all of our regulators and our lights have been converted to either 120 or 240 volt operation.
The only thing I know about it is that the open circuit voltage of a 6.6 A constant current regulator is treated as 5 kV class for construction. The circuits are very dangerous because a second ground fault is just a lesser amount of load and is adjusted for by the regulator. We used a lot of IL transformers to get 90 volts and then changed to MV lights with IL transformers.
We have finally gotten rid of all of our regulators and our lights have been converted to either 120 or 240 volt operation.
Re: Airport Lighting Series Circuit
It is true that airport lighting circuits are defined by the FAA Advisory Circulars and NEC requirements as such are not referenced however the NEC requirements provide good sound guidance and will be utilized for reference in future ACs. Due to the existing infrastructure that utilizes either 6.6 or 20 amp circuits series circuits it does make economical sense to keep this infrastructure but the full potential savings that LEDs offer will only be obtained when the series circuit transformers have a good power match with the LED fixture and the CCR efficiency is improved for the lower wattage circuit. The reduction in the power required will result in a less costly power distribution system that supplies the power to the CCRs. In addition safety can be improved and maintenance reduced by reducing both the amperage of the series circuit and the maximum open circuit voltages of the CCRs when powering an all LED circuit. In the future new all LED circuits that don't mingle with 5kv circuits may be able to use 600 volt cable and a smaller conductor . The circuit is a current limited circuit based on the current limiting ability of the constant current regulator (CCR). Nice to get all the comments.
It is true that airport lighting circuits are defined by the FAA Advisory Circulars and NEC requirements as such are not referenced however the NEC requirements provide good sound guidance and will be utilized for reference in future ACs. Due to the existing infrastructure that utilizes either 6.6 or 20 amp circuits series circuits it does make economical sense to keep this infrastructure but the full potential savings that LEDs offer will only be obtained when the series circuit transformers have a good power match with the LED fixture and the CCR efficiency is improved for the lower wattage circuit. The reduction in the power required will result in a less costly power distribution system that supplies the power to the CCRs. In addition safety can be improved and maintenance reduced by reducing both the amperage of the series circuit and the maximum open circuit voltages of the CCRs when powering an all LED circuit. In the future new all LED circuits that don't mingle with 5kv circuits may be able to use 600 volt cable and a smaller conductor . The circuit is a current limited circuit based on the current limiting ability of the constant current regulator (CCR). Nice to get all the comments.
- Location
- Bremerton, Washington
- Occupation
- Master Electrician
Re: Airport Lighting Series Circuit
Can you post a link to the new type of LED airport lights.
LED's have become very popular for traffic signal heads, in place of incandescent lamps. I have also heard of LED lamps for roadway or street lighting.
Can you post a link to the new type of LED airport lights.
LED's have become very popular for traffic signal heads, in place of incandescent lamps. I have also heard of LED lamps for roadway or street lighting.
flightline
Senior Member
Re: Airport Lighting Series Circuit
I am not picking at you, nor saying your ideads are without merit, sewardf, when I say that I don't believe t will happen anytime soon. The FAA is a stodgy bueracracy, that doesn't make radical changes, [ as this would be], quickly. The airlinr industry is not doing all that welll. And for many many municipalities that operate the airport facilities, their operating revenue, and much of that for improvement and expansion, [oooh...a dirty word to some here in Chicgo] are tied to the airlines. The utility bills for the operation of the runway lighting system, as many things I've found aren't always the priority for change. Saving money is important , yes, but it is sometimes curious and sad to see what can be sacrificial.
Airfield lighting is performance and relaibility driven; both attributes of LED technology, so as I stated it will be embraced, but not at the level I think you expect.
I see that you are a consultant. An airport construction consultant or one that works for the LED fixture people? Just curious. I/we have dealt with many consultants, from national firms to local ones. We have also been innundated by a number of fixture manufacturers pushing their wares.
We have gotten perfect FAA139 ratings, for a number of years now, due, in part, to the diligent work of the airfield electrical crew whaere I work. They have standardized on only -2- manufacturers for their airfield equipment. These manufacturers won our respect and work diligently every day to keep it. As such, we have a smaller, more universal inventory for airfield maintenance.
I also question how a fault somewhere along a 5 mile run length of cable being operated at this suggested 600 volt level would act with the regulators. Right now, we can partially operate a circuit that has gone to ground until it can be repaired.
I am not picking at you, nor saying your ideads are without merit, sewardf, when I say that I don't believe t will happen anytime soon. The FAA is a stodgy bueracracy, that doesn't make radical changes, [ as this would be], quickly. The airlinr industry is not doing all that welll. And for many many municipalities that operate the airport facilities, their operating revenue, and much of that for improvement and expansion, [oooh...a dirty word to some here in Chicgo] are tied to the airlines. The utility bills for the operation of the runway lighting system, as many things I've found aren't always the priority for change. Saving money is important , yes, but it is sometimes curious and sad to see what can be sacrificial.
Airfield lighting is performance and relaibility driven; both attributes of LED technology, so as I stated it will be embraced, but not at the level I think you expect.
I see that you are a consultant. An airport construction consultant or one that works for the LED fixture people? Just curious. I/we have dealt with many consultants, from national firms to local ones. We have also been innundated by a number of fixture manufacturers pushing their wares.
We have gotten perfect FAA139 ratings, for a number of years now, due, in part, to the diligent work of the airfield electrical crew whaere I work. They have standardized on only -2- manufacturers for their airfield equipment. These manufacturers won our respect and work diligently every day to keep it. As such, we have a smaller, more universal inventory for airfield maintenance.
I also question how a fault somewhere along a 5 mile run length of cable being operated at this suggested 600 volt level would act with the regulators. Right now, we can partially operate a circuit that has gone to ground until it can be repaired.
Who's gonna pay for all this? That's really all I'm saying.
mikeames
Senior Member
- Location
- Gaithersburg MD
- Occupation
- Teacher - Master Electrician - 2017 NEC
Re: Airport Lighting Series Circuit
What about Deicing problems?? Do LED lights provide enough heat output to keep themselves clear of ice and snow????? I dont know just a thought.... :roll:
What about Deicing problems?? Do LED lights provide enough heat output to keep themselves clear of ice and snow????? I dont know just a thought.... :roll:
Re: Airport Lighting Series Circuit
The LED circuit I envision would still be a series circuit running at a lower amperage than 6.6A and the regulator output voltage may be restricted to 600volts, hence 600 volt rated cable can be used instead of 5000 volts when there is no 5000 volt cable in the same trench or conduit. The benefits of the series circuit which allows you to have one unintentional ground and still maintain the operation of the circuit would still be with us. The lack of any heat generated does pose a problem for the elevated lights. The FAA is currently requiring a heater which will melt any snow or ice on the globe. This would be thermostat controlled and could use 10 watts of power. To convert an existing circuit to a more efficient circuit would require changing all the fixtures on the circuit to the LED light source and replacing the series circuit transformer with a transformer that is matched to the load of the light and then provide a new CCR that would also match the circuit load and have a lower amperage output and a specified maximum voltage of 600 volts.
The LED circuit I envision would still be a series circuit running at a lower amperage than 6.6A and the regulator output voltage may be restricted to 600volts, hence 600 volt rated cable can be used instead of 5000 volts when there is no 5000 volt cable in the same trench or conduit. The benefits of the series circuit which allows you to have one unintentional ground and still maintain the operation of the circuit would still be with us. The lack of any heat generated does pose a problem for the elevated lights. The FAA is currently requiring a heater which will melt any snow or ice on the globe. This would be thermostat controlled and could use 10 watts of power. To convert an existing circuit to a more efficient circuit would require changing all the fixtures on the circuit to the LED light source and replacing the series circuit transformer with a transformer that is matched to the load of the light and then provide a new CCR that would also match the circuit load and have a lower amperage output and a specified maximum voltage of 600 volts.
flightline
Senior Member
Re: Airport Lighting Series Circuit
Again, how do you intend to push 600 volts on even the #6 we use, for an aproximate 5 mile circuit length? And again, who will pay for all of this work? I commend your vision of what you believe airfield lightig should be, but at least for now, if you are talking beyond the theoretical, you must be building it in "your world", since very few people in mine have the resources to commit to such a large scale endeavor.
[ August 26, 2003, 08:44 AM: Message edited by: flightline ]
Again, how do you intend to push 600 volts on even the #6 we use, for an aproximate 5 mile circuit length? And again, who will pay for all of this work? I commend your vision of what you believe airfield lightig should be, but at least for now, if you are talking beyond the theoretical, you must be building it in "your world", since very few people in mine have the resources to commit to such a large scale endeavor.
[ August 26, 2003, 08:44 AM: Message edited by: flightline ]
roger willis
Member
- Location
- Texas
Re: Airport Lighting Series Circuit
Flightline, I to have worked on a lot of airport lighting and I don't think the 600 volts would push hard enough. The 6.6 amp system that we have works very well. I think the biggest inprovement in the series system was when we went to the solid state CCR's and did away with the machanical one's with the counter weights. But that was a long time ago.
Anyway, just my two cents.
Roger
Flightline, I to have worked on a lot of airport lighting and I don't think the 600 volts would push hard enough. The 6.6 amp system that we have works very well. I think the biggest inprovement in the series system was when we went to the solid state CCR's and did away with the machanical one's with the counter weights. But that was a long time ago.
Anyway, just my two cents.
Roger
flightline
Senior Member
Re: Airport Lighting Series Circuit
Roger, my point exactly! We have a few runs on which the home run is 2.5 miles. Your two cents are well taken. Sewardf hasn't yet disclosed which interest he respresents as a consulting engineer. I'm just curious; and it would provide a perspective on how sewardf is looking at things. Manufacturers are always trying to get us to use their products due to the prestiege that would come from the notarity of having their stuff installed at ORD.
We have about 100 airfield lighting circuits. Some closer to the regulators in the vaults than others. That would represent a huge number of airfield lightiing fixtures, from in-surface, to rnuway edgelights, taxiway, informational signage, LAHSO, and the numerous other types we have. Perhaps I'm being snobbish because of where I work, but I'm also proud of what we do, and the scale we do it on. Especially after the plow trucks have left the runway after a snowstorm.
The airline business, as we all have seen on the news, is not in the best financial shape. Since they basically end up paying for most everything, I can't imagine any of them willing to replace a system that seems to work, for another similar system.
Roger, my point exactly! We have a few runs on which the home run is 2.5 miles. Your two cents are well taken. Sewardf hasn't yet disclosed which interest he respresents as a consulting engineer. I'm just curious; and it would provide a perspective on how sewardf is looking at things. Manufacturers are always trying to get us to use their products due to the prestiege that would come from the notarity of having their stuff installed at ORD.
We have about 100 airfield lighting circuits. Some closer to the regulators in the vaults than others. That would represent a huge number of airfield lightiing fixtures, from in-surface, to rnuway edgelights, taxiway, informational signage, LAHSO, and the numerous other types we have. Perhaps I'm being snobbish because of where I work, but I'm also proud of what we do, and the scale we do it on. Especially after the plow trucks have left the runway after a snowstorm.
The airline business, as we all have seen on the news, is not in the best financial shape. Since they basically end up paying for most everything, I can't imagine any of them willing to replace a system that seems to work, for another similar system.
roger willis
Member
- Location
- Texas
Re: Airport Lighting Series Circuit
Like the old saying goes "If it isn't broke don't fix it"
Like the old saying goes "If it isn't broke don't fix it"
Re: Airport Lighting Series Circuit
It has been a while since I have visited this site and it is good to review the old comments. A lot has gone on since my last comments but I can report that work continues on coming up with a new series circuit that is more reliable and safer to work on than the present 6.6 or 20 amp circuit. I recently gave a presentation on this subject at the IES Aviation Lighting Committee annual technical meeting in Austin, TX. My good friend Gene Gotlieb from O'Hare was there and his input as always is most beneficial. With regard to a lower voltage being capable of powering a long series circuit we know that the voltage needed is dependent on the amperage required and the load in ohms. And as you indicated the series ciruit will still operate just fine with one unintentsional ground since the circuit is a floating circuit with no reference to ground back at the CCR. If the new lower power series circuit is agreed to be the way we will go it will become the standard for those circuits that are totaly converted or installed as circuits hading 100% LED lighting. The equipment used in this circuit will also be as specified in new Advisory Circulars and as such will be available for AIP funding. As you indicate this is not going to happen overnight but there is a lighting revolution underway which not only involves airport visual aids lighting but will involve the whole lighting industy sooner or later. My work involves several area of airport lighting. The one we are having our discussion about involves my support for FAA AND 520. Keep the dialogue going
It has been a while since I have visited this site and it is good to review the old comments. A lot has gone on since my last comments but I can report that work continues on coming up with a new series circuit that is more reliable and safer to work on than the present 6.6 or 20 amp circuit. I recently gave a presentation on this subject at the IES Aviation Lighting Committee annual technical meeting in Austin, TX. My good friend Gene Gotlieb from O'Hare was there and his input as always is most beneficial. With regard to a lower voltage being capable of powering a long series circuit we know that the voltage needed is dependent on the amperage required and the load in ohms. And as you indicated the series ciruit will still operate just fine with one unintentsional ground since the circuit is a floating circuit with no reference to ground back at the CCR. If the new lower power series circuit is agreed to be the way we will go it will become the standard for those circuits that are totaly converted or installed as circuits hading 100% LED lighting. The equipment used in this circuit will also be as specified in new Advisory Circulars and as such will be available for AIP funding. As you indicate this is not going to happen overnight but there is a lighting revolution underway which not only involves airport visual aids lighting but will involve the whole lighting industy sooner or later. My work involves several area of airport lighting. The one we are having our discussion about involves my support for FAA AND 520. Keep the dialogue going
- Status