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I'm pre-wiring a distribution panel for future installation into my retirement home in the Philippines. I've read that grounding the DP to an earth rod or equivalent should require a minimum 6AWG/10mm2 wire(?) However in the metal DP which I purchased, the earth busbar only has screw holes large enough for 6mm2 wire. So my question is whether it is ok to split the wire strands in the 10mm2 ground wire into 2 separate bundles and insert each of them into a separate screw hole in the same earth busbar? I would use ferrules to ensure a good contact. It seems logical that it should be ok, but I'm not an electrician (it's undoubtedly obvious!) and wonder if there are any safety issues associated with this?

Thanks all for your suggestions to replace the busbar with one with bigger screw holes. However one (strange?) thing I have discovered is that the DP appears to be coated with a non-conductive paint. I learned this by using a multimeter to measure the resistance between any 2 points in the metal DP enclosure. This also applies to the earth busbar which is attached with small steel screws to the DP metal chassis, but when using the multimeter shows very high (OL) resistance readings using one probe on the busbar and the other probe on the DP chassis. I suppose I will have to sand off the non-conductive paint to expose the bare metal before mounting the new busbar but wonder if this is 'standard' DP box design? Thanks for your thoughts.

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  • \$\begingroup\$ There should be a safety code that specifies this requirement. Is there a Philippines equivalent of the NEC? This may help as well. \$\endgroup\$ – relayman357 May 17 '20 at 13:34
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There shouldn't be any safety issue with this, however, a bigger bus bar shouldn't be very expensive (Approximately $10 in the U.S., I'm not sure about prices in the Philippines) and it's an easy bolt-in upgrade.

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That wouldn't be allowed in NEC.

The earth part of the bus bar certainly ought to have one lug with a hole large enough for this wire. However, since the bus bar is bolted to the steel chassis of the panel, it should be acceptable to get a lug that is large enough and bolt that to the chassis also.

Also, ground bars are available as add-on accessories. You may be able to buy an accessory ground bar that has a large enough hole.

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