Sizing CB's for RTU's

[trickett]

Hi I'm working on a project in Central Florida and I have an engineer confusing me.

The code (Article 110-3) states that systems must be installed as listed or labeled and we have an RTU with a name plate that specifically states that the maximum circuit breader size is to be 35 amps.

The engineer has put this RTU on a 70 amp breaker and requires us to use number 4 conductors for a short run. Does this make any sense to anyone?

Same engineer requires us to use a number 2 for a 50 amp RTU on a 100 foot pull.

Same engineer selects Brown, Orange and Yellow conductors for both high and low voltage applications and Black, Red and Blue for both high and low voltage applications when the code (article 240) requires that all systems and phases be coded.

 

[don_resqcapt19]

Re: Sizing CB's for RTU's

Same engineer selects Brown, Orange and Yellow conductors for both high and low voltage applications and Black, Red and Blue for both high and low voltage applications when the code (article 240) requires that all systems and phases be coded.

What code section requires color coding?
Don

 

[kiloamp7]

Re: Sizing CB's for RTU's

The way you describe it, the RTU must have 35A OCP somewhere in its ckt.

Is the engr telling you to put a 70A bkr. with the #4 wire electrically "upstream" of the 35A OCD ? If so, thats probably legal, but do not know the reasoning behind it.
Give us more information on the application & proposed circuitry.

The color code question is a whole different issue from wire sizes & OCP.