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Splice & terminal block voltage ratings
- Thread starter SunFish
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Carultch
Senior Member
- Location
- Massachusetts
Do terminals blocks and splices have a voltage rating that is AC or DC specific? If I have a terminal that is rated for 600 V can I use that on either AC or DC systems?
Insulation on a terminal block is not AC/DC specific. Load break and overcurrent devices are where you have to watch out for this, due to the lack of zero crossings in the DC voltage system.
600Vac ratings actually have to withstand 850V instantaneous, but unless a datasheet specifies it, you are limited to 600V whether AC or DC. While it could exist in theory, it is very rare (if ever) that you have a field-installed product that is NOT rated for AC voltage, where it would be rated for exclusively 600Vdc and not 600Vac.
Last edited:
- Location
- Placerville, CA, USA
- Occupation
- Retired PV System Designer
As noted in another thread, once you get into MV and higher voltages anything with certain types of insulation has the possibility of being rated for DC only. And although I am not aware of any specifics, some insulation types might degrade when exposed long term to DC but be OK with AC of the same voltage. (Water trees, for example?)Insulation on a terminal block is not AC/DC specific. Load break and overcurrent devices are where you have to watch out for this, due to the lack of zero crossings in the DC voltage system.
600Vac ratings actually have to withstand 850V instantaneous, but unless a datasheet specifies it, you are limited to 600V whether AC or DC. While it could exist in theory, it is very rare (if ever) that you have a field-installed product that is NOT rated for AC voltage, where it would be rated for exclusively 600Vdc and not 600Vac.
Not at all likely to happen with terminal blocks. MV splices are subject to the same caveats as MV wiring.
shortcircuit2
Senior Member
- Location
- South of Bawstin
Make sure the blocks are listed for the application. Many terminal blocks are only a UL recognized component for use in the assembly of equipment that is listed as a whole. Listed field installed terminal blocks must have covers for the exposed terminals.
Make sure the blocks are listed for the application. Many terminal blocks are only a UL recognized component for use in the assembly of equipment that is listed as a whole. Listed field installed terminal blocks must have covers for the exposed terminals.
Good point Shortcircuit2. These are actually insulated terminal blocks that I was curious about, polaris lugs specifically.
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