Hi,

Looking to start surveying a number of Electrical panels (24hr paper finishing plant equipment) what sort of frequency is normal for this type of survey 3mths, 6mths, yearly ?

Thanks for any info,

Co.

NFPA 70B 1998 Edition "Recommended Practice for Electrical Equipment Maintenance" section 18-17.5 states: "Inspection Frequency and Procedures. Routine infrared inspections of energized electrical systems should be performed annually prior to shutdown. More frequent infrared inspections, for example, quarterly or semiannually, should be performed where warranted by loss experience, installation of new electrical equipment, or changes in environmental, operational, or load conditions."

EPRI Infrared Guide Revision 3 states roughly that critical components should be monitored quarterly and vital components should be monitored quarterly above 480v and every 6 months at 480 volts and below.

In the end it's a cost-benefit analysis based on your situation. If you're contracting out, the cost per survey is high and you might not do it as often. If it's in-house and you already paid for the equipment, the cost per survey is lower so more surveys might be worthwhile.

I work at a large nuke plant with an in-house progrma and we do a very few things monthly, most critical things quarterly, other equipment 6-months or a year.

Electricpete, do you have the links to the documents cited above?

NFPA70B is available for around $50 at www.nfpa.org

The EPRI Infrared guide I suspect would be several thousand dollars for non-EPRI members (free for EPRI members).

If you are looking for a free standard, I think Howard (motordoc) has posted one from NAVSEA on his website with some guidelines on infrared inspections.

Thanks Pete. I got the NAVSEA & INFRASPECTION documents which do not mention frequency explicitly.

Btw, is there any industrial Electrical standard for thermography eg for oil & gas offshore industry? The NRPA & EPRI may be too excessive in their requirements.

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What equipment are covered under the NFPA 70B? Because the NFPA is concerned about fire, we are worried that it's too stringent for the offshore oil & gas industry, what do you think?

The title of NFPA70B is "Recommended Maintenance for Electrical Equipment" and it applies to industrial electrical equipment.

Here is the scope statement: "This recommended practice is confined to preventive maintenance for industrial-type electrical systems and equipment and is not intended to duplicate or superseded instructions that electrical manufacturers nromally provide. Systems and equipment covered are typical of those installed in industrial plants, institutional and commercial buildings, and large multifamily residential complexes. Consumer appliances and equipment intended primarily for use in the home are not included."

I would think offshore oil/gas generally falls under the scope of industrial equipment. In the end, this document is a guideline / recommendation only, so their is plenty of room for whatever judgement you want to apply to your situation. It seems that the more severe the consequences of failure, the more frequent inspections are warranted. Without knowing the industry I would think there can be lots of bad things that come from failures of offshore electrical equipment. Fires, loss of function of equipment, etc. In some ways I picture offshore similar to shipboard. I always thought that shipboard equipment was generally viewed as more critical because all the equipment is so close together that it is easy for damage to spread and there if spreads too far there is nowhere for the people to go. Also the systems may be critical. Finally there may be more degrading influences on electrical equipment due to salt environmetn?

Thanks Pete for the link, I managed to read the NRPA. That's good.

Having read NFPA 70B, it was clear it's not too heavily focused on fire protection specifically which we could possibly think because of the agency name contains the word "fire". The 2002 edition contains maintenance intervals in Annex I. I thought it will recommend us to check all potential sources of fire as often as possible that the maint program would be excessive.

Furthermore, it's related to the National Electrical Code.

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