---
title: Medium Voltage
tags:
  - topic/construction/electrical
  - type/encyclopedia-entry
up: "[[electrical]]"
---
# Medium Voltage

"Medium voltage" refers to voltage systems greater than 600V.

## Insulation Level

> [!example]
>
> > [!cite] 343 Madison Avenue Project Specifications, emphasis added
> > 2.2 MEDIUM VOLTAGE CABLES (CON EDISON)
> > * ...
> > * H. Construction
> >     * ...
> >     * 3. Insulation
> >         * ...
> >         * c. _The minimum average insulation thickness shall be not less than 175 mils._
> > The minimum thickness at any cross-section of the insulation
> > shall be not less than 90% of the specified minimum average thickness.
>
> In this case 100% insulation level is appropriate for 15kV conductors.

[[nfpa-70_311_mv-conductors#311.10(B) Thickness of Insulation and Jacket for Nonshielded Insulated Conductors.]]

| Voltage Rating | Insulation Level | Insulation Thickness |
| --------------:| ----------------:| --------------------:|
|            5kV |             100% |              90 mils |
|            5kV |             133% |             115 mils |
|            5kV |             173% |             140 mils |
|            8kV |             100% |             115 mils |
|            8kV |             133% |             140 mils |
|            8kV |             173% |             175 mils |
|           15kV |             100% |             175 mils |
|           15kV |             133% |             220 mils |
|           15kV |             173% |             260 mils |
|           25kV |             100% |             260 mils |
|           25kV |             133% |             320 mils |
|           25kV |             173% |             420 mils |
|           35kV |             100% |             345 mils |
|           35kV |             133% |             420 mils |
|           35kV |             173% |             580 mils |
