OSG Table 7.1(i)

kingeri · Apr 30, 2012

Table 7.1(i) lists standard circuits that can be installed without calculation. The radial circuits are all listed as having a terminal load. Can they equally be used for socket circuits? Just to settle an argument!

morph · Apr 30, 2012

dont like table 7.1 as not all the circuits work out for volt drop even though they are stated as ok , best do it the right way imo

Silly Sausage · Apr 30, 2012

kingeri said:
Table 7.1(i) lists standard circuits that can be installed without calculation. The radial circuits are all listed as having a terminal load. Can they equally be used for socket circuits? Just to settle an argument!

The lengths given will be worst cases. I would say that if the total load (Ib) is at the end of the radial, the circuit will be carrying full current along its entire length, which will result in a shorter circuit length to keep VD<5%. If that makes any sense!!!

But yes, they can be used for socket circuits.

kingeri · Apr 30, 2012

Archy Styrigg said:
The lengths given will be worst cases. I would say that if the total load (Ib) is at the end of the radial, the circuit will be carrying full current along its entire length, which will result in a shorter circuit length to keep VD<5%. If that makes any sense!!!

But yes, they can be used for socket circuits.

Yes, that's perfectly logical.

Morph, I have never used the table, but was having a look through the green OSG (only just 'upgraded' from red) and was wondering why they included it.......yes it makes life easier, but I would only trust my own calcs for a circuit I'm installing. It seems to be aimed at folks who don't know how to calculate voltage drop, select the correct cable etc. You say the voltage drops don't always work out....this in itself to me is a major issue with this table.

morph · Apr 30, 2012

kingeri said:
Yes, that's perfectly logical.

Morph, I have never used the table, but was having a look through the green OSG (only just 'upgraded' from red) and was wondering why they included it.......yes it makes life easier, but I would only trust my own calcs for a circuit I'm installing. It seems to be aimed at folks who don't know how to calculate voltage drop, select the correct cable etc. You say the voltage drops don't always work out....this in itself to me is a major issue with this table.

its just a quick reference guide, guide being the operative word... always best to calc the circuit yourself...