change of way colour to conot standard distribution power line Voltage

can anyone help with how to change the way colour MV power line so as to suite colour code when lins of different are merged pls.

Hi and welcome to OSM and the forum

OSM is just a database and has no color information regarding voltage. When it comes to colors the program generating the image(s) from the data in the database is responsible.

So please tell us which program you use to visualize OSM-Data.

Thanks for your kind and quick response to my request.
however, the mapping app using to visualize the program is josm (Java Open Street Mapping) and seriously need to change the way colour to denote my voltage level.
please help

You can change the way JOSM displays objects via style-sheet. However I never worked with style sheets in JOSM. https://josm.openstreetmap.de/wiki/Styles/Coloured_Streets describe how to change colors for streets and buildings, so it might give you a hint on how to change the default settings or add additional styles for power=line .

After playing around with the additional style sheet “Power Mapping Additions” from SSherpa+prabhasp I came up with the following:

meta 
{
    title: "TEST Power";
    description: "TEST Power";
}

way[power=line][!voltage] /* power lines (without voltage) are blue (default)*/
{
    color: blue;
	text: eval("No voltage");
}

way[power=line][voltage] /* power lines (with any voltage) are darkred */
{
    color: darkred;
	text: "voltage";
}

way[power=line][voltage=1500] /* power lines with voltage=1500 are green */
{
    color: green;
}

way[power=line][voltage>1000][voltage<1500] /* power lines with 1000 > voltage < 1500 are light green */
{
    color: lightgreen;
}

way[power=line][voltage>1500] /* power lines with voltage > 1500 are yellow */
{
    color: yellow;
}