400V & 110V in same Junction Box?

[electricnova]

Hi,

I am a design engineer (2 years out of apprenticeship).

I am in the process of amending some designs that are not quite to our company standards.

There is currently a junction box that houses a 400V supply and a 110V supply with no segregation of the DIN rail terminals. This doesnt seem ok to me.

Is it ok to have this set up or should I make the attempt to segregate the two supplies within the junction box panel?

Note: I would have preferred two separate junction boxes but this is not quite an option at this moment.
I am in the UK.

Thanks

 

[Rockingit]

So long as the insulation factor of all of them is to the highest voltage present and everything is clearly labelled (is it actually 110v or is it 55v CTE?) then I don't believe there's an issue. However, I'm in agreement that it's not a great way forward - why not just use a couple of spacer blocks inbetween?

 

[brianmoooore]

Both come within the definition of "low voltage" so no segregation required, but, as above, a spacer block wouldn't go amiss.

 

[pc1966]

Sometimes I put in an G/Y earth block between such sections even if not needed. Provides a little more reassurance!

You can also get separator sheets for many DIN rial devices, or another option is to use different colours to identify different voltages.

But simplest option if enough space is to use a couple of end-stops and make it like two blocks on the same rail.

 

[James]

I too tend to use the din mount earth terminals as spacers and end blocks because they generally clamp on to the rail and prevent movement.

 

[Lucien Nunes]

If either of the supplies is electrically separate, then more than basic insulation is required between them. If not then as mentioned it's technically acceptable but IMO poor practice. At the very least I tend to put an end cover on the open side of the terminal to double-up the insulation, but space permitting an earth terminal or endstop is better.

Historically in theatre lighting we often had to deal with what one might call 'installed multiple extension leads' where dozens of circuits ran between plugs in one location and sockets in another. When any plug isn't engaged in a socket its pins are exposed to the touch, so its circuit conductors need to be suitably insulated from those of the next circuit which might be energised. Within the cables each has its own insulation but when they are all terminated to DIN terminals on a rail, there's only one layer of insulation between the metal parts of one terminal and the next. DIN terminals were not the only situation where this inter-circuit insulation was marginal (19-pin connectors were another) and everyone did it, but it was a frequent topic of conversation.

 

[Chris1234]

Just a terminal block separator if your using different colour terminal block, or different colour connection strips.
Or use an earth terminal block to separate them.