Type 1 SPD at Mains Intake Advice Please on a TNCS

[pc1966]

I would put the SPD in a metal DIN enclosure. If something goes wrong / big strike they might get very hot (though they have solder links to disconnect in that case).

If you can run the cables (25mm tri-rated?) from isolator to DIN box to board then use the sort with the double connections so they have practically no additional inductance. This is the sort I have used (TN-S style):

Type 1+2 Lightning Current and Surge Arrester (KM1+2-25-4+0 SC) - Kingsmill Industries

System: Three Phase TN-S & TN-C-S/4 Pole Nominal Voltage: 230V AC

kingsmillindustries.com

They also do one more like the common sore with different N-E protection for TT systems:

Type 1+2 Lightning Current and Surge Arrester (KM1+2-25-3+1 SC) - Kingsmill Industries

System: Three Phase TT/TN-S/4 Pole Nominal Voltage: 230V AC

kingsmillindustries.com

They are OK with 125A supply fuses for "V wiring" (Kelvin 4-ware style), not requiring any additional protection.

 

[John-]

Thanks @pc1966 I already have the antisurge device. Will look at ours next time. I was going to just spur off the isolator, hence the lugs so the isolator would have three sets of cables coming out - two to the loads and one set to the SPD. If there was any doubt about the terminals in the isolator taking the three sets of lugs, i was going to use Henley blocks and use insulated and sheathed tri rated cable - or just tales. I need to go back to site and check the options.

 

[pc1966]

OK!

Just to add if you had space for the likes of the Hager JK116EA3 (assuming it has to meet amendment 3, I used the glazed one for industrial site) you could put in a 50A D-curve MCB for the SPD if worried about the DNO fuses (or want a quick means of isolation for IR testing) and you could also put in some linked DIN terminals to allow 4 connections for each of L1-3 & N:

• power in
• SPD MCB feed
• board #1
• board #2

All with minimum distance and inductance to the SPD.

The likes of these terminals allow 35mm cable to be attached and are rated at 125A, but I have not checked if they clear the DIN box (can do later):

1SNK516010R0000 | Entrelec Grey ZS35 Feed Through Terminal Block, 35mm², ATEX, 1 kV ac | RS Components

uk.rs-online.com

These are the jumper bars to link an adjacent pair of terminals together:

1SNK916302R0000 | Entrelec JB16 Jumper Bar for Terminal Block | RS Components

uk.rs-online.com

You get them up to 10-way but not from RS, think I got mine from these folks:

Entrelec 1SNK916310R0000 JB16-10 10 POLE JUMPER BAR | Kempston Controls

Entrelec 1SNK916310R0000 JB16-10 10 POLE JUMPER BAR part of DIN Rail Terminal Blocks and Accessories, distributed by Kempston Controls. Shipping to 240+ countries worldwide.

www.kempstoncontrols.co.uk

 

[telectrix]

as it is non-domestic, you don't need to use a metal enclosure. use plastic.