LV Conductor colours used in Mexico? 1

[LDMaughan]

Hi there,

Can someone please clarify the conductor colours used in Mexicos standard 3-phase and single phase LV mains circuits?

I understand that the voltages are:-
220v 3 ph @ 60hz
127v 1 ph @ 60hz
is this also correct?

Thanks in advance.

 

[jspigolon]

You will always find this relationship:

phase A - red
phase B - blue
phase C - white

For the other question:

if you are working in LV distribution system, normaly you will be seen 4 cables in a 3 phase system (3 phases and 1 neutral) and 2 cables in a single system (1 phase and 1 neutral). Therefore, the voltage between two phases is 220V and between one phase and neutral is 127V. The frequency in Mexico is 60Hz.

 

[LDMaughan]

Thanks jspigolon,

However, what colour would the previously mentioned neutral conductor be?

 

[freddycor]

LDMaughan:

Only to add a little more:

The color of the phases have not definition like "standard", however is common practice to use the NEC definitions ( like jspilogon said ), only in case of "high leg" usage, (in phase C) is orange or red.
Also is very common find voltages 120/240 Volts ( in public service ) in single phase and three phase with high leg, coming from two single phase transformers in open delta connection.
The standard color for neutral is WHITE or GRAY, and for ground insulated conductors of equipments is GREEN or GREEN with YELLOW bands.
I dissagree with the usage of WHITE color in C phase, because is the normative color for NEUTRAL.

" Todos somos ignorantes, pero de cosas diferentes..."

 

[LDMaughan]

I'm just getting more and more confused!

Surely phase A & phase C can't both be the same colour?

However, there is no such thing as a normative neutral colour. Over here in the UK Neutral colour used to be Black, which is currently being changed to Blue which is supposed to be a European 'standard'.

…Back to my original question, can someone please clarify the phase, neutral, and earth conductor colours for both single and 3 phase LV electrical system used in Mexico?

[img]http://members.aol.com/_ht_a/ldmaughan/Media/smiling.gif[/img] [ ¿puede alguien clarificar por favor la fase, hilo neutro, y los colores del conductor de la tierra para escogen y sistema eléctrico del LV de 3 fases usado en México? ]

 

[GamezBeCJ]

Maughan:

In Mexico the main standard for electrical installations is NOM-001-SEDE-1999. According to this standard the color identification should be as follows:

Article 200-6: Identification means for grounded conductors
"...it should be identified by means of an external continuous jacket of white or light gray color..."

Article 210-5: Color code for derivated circuits
a) "...if it is required to install diferent systems in the same conduit, the grounded conductor of the other systems should be white or light gray with a colored strip diferent from the other conductors..."

b) "The grounding conductor for equipment (machines) in a derivated circuit, must be identified by a continuous green color or a green color with a yellow strip..."

Article 215-8: Identification means for highest voltage conductor (refering to feeder circuits)
"... the highest voltage conductor should be identified by an external finish of orange color..."

It is an extensive standard, which practicly rules every installation in Mexico, I would recomend you to take a look.
Hope this helps.

Regards


Carlos Gamez, P.E.
Industrial Consultant
Transformer Specialist