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I don't have a choice. These are steam tunnels. The lights are meant for emergency egress to meet life safety code in the US. I cannot have anything with the ballasts because of the heat. There are no PAR lamps at 240 V in the US. Howeeverthere are regular incandascent lamps are avaialable...

Is there a manufacturer who makes a PAR lamp or any Incandescent lamp at 240 Volts? if posible in medium base? Is there a local [US] manufacturer who makes a booster transformer for this purpose ?

I am working on emergency egress lighting design for a half a mile tunnel. The temperature is about 154 Deg. F. Because of this higher temperature, the 20 amp circuits usually takes No 12 AWG were derated to No 10 AWG per NEC. Again if I derated the same 20Amp circuits for 5 % Voltage Drop per...

I have situation where I have a switchgear fed by four 750 kva transformers from the Utility. Since switch gear is nearly 40 years old with many loads that are unknown. I have requested a consultant to meter the current loading on switchgear in order to ensure that the switch gear can take any...

I am looking for Formulas or/and Calculations to compare Florescent Lamp Ballasts for a Energy and Cost Savings study based on their Ballast Factors. Any help or directions you can offer me will be greatly appreciated. Thank you in advance

My question is which side, Primary or Secondary side it is normaly grounded?

I like to know which side of the Transformer on 13.8 KV /277-280v setup the Lightning Arrester is normally grounded as a standarded practice?

I need help on finding the some resources or formulas on calculating or evaluating the rating of wet cells based on its discharge time. For example if a wet-cell discharges in 20 hours at 4.5 volts when fully charged and at the same time it takes 10 hours to discharge at 7.5 Volts. How do you...

I want to know on what Standard typical Generator Factory Test is usually performed? I am invited for a Factory test on a 1000 KW Generator. I would like to look up some requirements and standards besides our project specifications. Thank you in advance.

I would like to know whether I can run power [208 v], telephone and cable TV in one conduit for a private home/vacation home project. It is 350 feet run. I don't see any code violation in doing this, however will there be any interference or cross talks? Please advise. Thanking you in advance

I have to witness a low voltage switchgear factory test soon. I only have project specifications which do not say much. I like to know if there is any literature on line where I can look up for some of the important testing requirements

I wonder whether someone can provide me some references as to how to calculate losses [ in watts] based percentage of No- load, Half-load and Full-load conditions for 3-phase motors. Thank you in advance

I would like to know what the precautions those are necessary in de-energizing electrical systems [medium/ low voltage switchgears and others] in terms of electrical safety. Can some one explain me the dangers involved if correct procedures were not followed? Thank you in advance.

I am looking for wiring diagram as from a lightning protection system designer's view point that starts from lightning terminal on the roof then go through the lightning arrester, connects to the primary of the service transformer then to the system or building ground. The transformer can be...

One of the engineers I work with wants to provide several transformers to establish ISOLATED GROUNDING in a regular office building setup. Is this a standard practice? I was under the understanding that the isolated grounding conductor has to be taken directly all the way to the building’s...

Is failure of insulation resistance test on one phase[Phase A] is it good enough to replace an MI cable $100,000+ worthjust to replace one phase?. This thing feeds a Fire Pump.

I have the following reading on 800 feet MI cable for insulation resistance. The reading on the Phase to ground [A-G] was too small in the range of 2.7 to 2.9 Meg-Ohms. Where as the manufacturer’s specification for MI cable is 25 Meg-Ohms and larger. The reading on Phase B and are unusually too...

I have had vast difference in reading on insulation- resistance for MI Cable, the digital meter [by YOKOGAWA -24060 MEAS] shows about 6.0 Meg Ohms and an analog [MEGGER by BIDDLE] meter shows about 7 Gigs for the MI cable. The reading with both meter were taken more than twice and appears to...

Hello there, I am looking for source of information on variable frequency drives that has to do with electrical design and distribution issues. I am also seeking this information to prepare for professional licensing. I understand that NCEES seems to require more than a reasonable knowledge...

I am looking for a decent self help book, preferably with lots of design problems and solutions. In the area of circuiting using by-polar transistors, FET, OP-AMPS, and Digital Circuits etc. This is my line of interest and also I want to use this to prepare for Professional Licensing exam for...