I am wondering how to handle a fire spinkler system that had a broken line. This break watered down 4 stories of a building, 50 to 99% saturation, all wired in mc. What would be the neccessary steps to fix properly. I have tried to contact manufacturers of products with no defined answers. The authority having jurisdiction stated all needs to be replaced, is this neccessary or are there other ways to proceed.

Fire pump piping - If I am going to feed the fire pump controller - can I use EMT to feed the fire pump controller - than GRC from fire pump contoller to fire pump - please explain

We have two feeders to fire pump controller - one normal power and the other EM power - we use RHW 2 hour rated fire pump wire for normal power and install per UL listing - use EMT steel set screw fitting and supported every 5 ft

Mike, Was not able to open this link. Jim Shafer

Hi Mike:

Given the start of Hurricane season and the increased interest of applying generators to serve as back up power systems, It would be great to have a news letter to discuss single phase generator sizing and proper connections. Specifically discussing generator surge watts and requirements for startings highly inductive loads such as hermetic compressor motors such as those found on central and room air conditioners. There is an apparent information void on the subject.

It would also help to learn how to estimate the surge watt requirement given the nameplate of the AC unit.

Should you have any questions or additional comments please e-mail me,

It has been my experience involving submersible electric pumps (low voltage class), that intrusion by water represents a costly repair. I imagine restoration cost of medium and high voltage equipment would in most cases exceed replacement cost. As the low voltage molded case circuit breakers I have worked with are assembled with rivets, I wonder how they could be repaired.

I am not sure I agree with the document wiht regards to transformers. They are nothing different really than an electric motor in thier construction. A dry type transformer should be able to be steam cleaned and chemically degreased if neccesary. Then it can be oven dried and redipped in varnish megger tested and should be fine as far as I am concerned. your comments?

I agree with Joe Stewart's comment and can offer the following. Dry type transformer insulation is primarily composed of Nomex a hygroscopic material, This material attracts and retains moisture. Steam cleaning is good for new equipment but the force generated by the steam may enter old and brittle insulation causing it to delaminate. Grease and dirt may not be as prevalent as in a generator or motor due to the lack of moving parts and bearings. Typically dust, wet or dry are the most common contaminants. Vacuuming the windings is a good idea as opposed to blowing compressed air that may force the contaminants deeper into the insulation.

I have been successful in drying out electrical apparatus on site using DC welders. A three phase transformer and or generator/motor can have all six leads brought out, (line and neutral) OF BOTH PRIMARY AND SECONDARY WINDINGS and connected in series and have a DC current run through them for the I squared losses to gradually generate heat and dry the winding from the inside out. The temperature should not increase by more than 5°C per hour until the final temperature of 100-125°C is attained. A rapid rise in temperature could cause steam bubbles to damage the insulation. There will be no transformation of voltage as there is no time varying flux.

IEEE 95 and IEEE56 show the trend experienced when drying out windings. Typically Megger values will decrease with an increase in temperature until all of the moisture is removed. Then megger readings will rise.

If an oven is available use it. Typical dry out temperatures were in excess of 250°F, but in no case should they exceed the temperature class of the insulation. Dips and bakes are a good way to seal old and cracked insulation.

Thanks to all, And I hope this helps,

i agree that nomex is hydroscopic in its bare form jowever when it is used with a standar resin system it wick the varnish very nicley to give the material a very high resistance to moisture intrusion. Sealling it ou if you will. Most of todays transfromers are also varnished using a vacuum impregnation insulation system which further gaurds against intrusion of moisture etc because it drives the varnish deep into all the little tiny crevasses in the lamination stacks and the winding itself. Anyhow a good cleaning and a bake out to dry these items along with a redip and bake can bring a lot of these units back to very good condition in my opinion. of course any questionable megger reading after the unit cools from the oven then dont hesistate to scrap it..