Power cable

Hi all, I would like to know how do ya'll determine the kind of electric cables ( wire guages) to be used for different applications. I'm working in a small company and the people here are trying to figure out the electrical cables to be used in an oil field. Does anybody have any idea??

Search the Web for 'ampacity tables'.

Now, oil industry may have its own special requirements - better talk to someone who knows.

The fact you are working in the oil field means that you
must use the national electrical code. section 500-5??
for requirements for installation. then look at table 310.16 for ampacity and table 310.15 for derating of the wire.

there is a lot more to what i have posted when doing electrical work and especially in hazardous areas like oil fields.

regards,
james

everything is run in sealtight with TMCX connectors. wire size depends on load.
the important thing is that gas can't travel up the conduit into the control rooms or explosion proof boxes. No sparks allowed. most of the area is NEC class 1 div2 with a few div 1 areas so read up on that in the NEC codebook

The short but maybe embarassing method is to ask your customer what he wants / needs. The embarrassing part may be when he says "youre supposed to know that stuff - what do I need you for?

To answer your question you need to know what the load demand is ie current, voltage
and if motor start current and max overload current,
lenth of wire run, how many conductors in cable or conduit, ampbient temperature,
environment stuff like dry or in wet weather, if in a combustible atmosphere (gas, liquids, combustible dust etc)
I cannot think of what else I am forgetting.

You need to get copy of a good electrician handbook and the NEC since you are in USA and start studying.

Dan Bentller

from my knoweldge...what ever voltage aboive 240vac are consider
power cable ...but each manufacturing have diffrent requirment..
feed mill,,gas mill, or oil have special requirment ..
u may follow ur national code for guideness

Thanks ya'll for the help. I have start reading NEC codebook.

Also read the section on motors in the NEC. It has some additional requirements on how much ampacity to account for.

Personally, I like the NEC Handbook, since it also gives some additional explanation and examples beyond just the text of the code.

If you do not have one you can order from here: http://www.nfpa.org/catalog/product.asp?pid=70HB11&order_src=B119

In the oilfield we mostly use CLX cable.The actual connector makes the box explosion proof or not. Readhead gland connectors on CLX is for explosion proof. Silverhead gland connectors on CLX is not. Most jobs i have done, were classified on prints as class 1 div 1 or div 2. Wire sizing depends on ampacity,deration factors, and other conditions. Shoot me an email([email protected]) with motor and amp spacifics, and i will try to help you in your search.