What is the difference between a 10A GPO and a 15A GPO?
There has been much discussion on other threads about the differences and similarities. Some have suggested that 15A GPOs are more durable and less likely to melt or burn at 15A than a 10A GPO. Others have suggested that the internals are probably the same but with a different face plate. I thought it would be interesting to look inside both a 10A GPO and a 15A GPO to see if there are any differences.
The most common 10A GPOs are a double outlet variety, but as 15A GPOs are only available as a single outlet, I thought it would make more sense to compare a 10A single GPO with a 15A GPO. The brand and model/series were also kept the same. I choose a brand and model that is popular in Australia and commonly used by electricians. The samples are from a "trade" pack as purchased by electricians rather than the "retail" package version as sold in some hardware shops.
Figure 1Notable difference are that on the 15A unit there is an extra tab of black plastic below the Earth pin. The colour rings are also slightly different: On the 10A unit the colour rings (Green on the Earth and red on the active) are full circles; Whereas on the 15A unit they are half circles. Although not apparent in this photo, the white front plate of the 15A unit also has a moulded section that mates with the extra tab of the black plastic.
shows a front view of the two GPOs. The 15A unit is on the right. Notable differences are the size of the Earth socket and the "15A" in black on the switch of the 15A version. Figure 2
shows a rear view of the two GPOs. Again, the 15A unit is on the right.
Figure 3Notable differences are: that the 15A unit has the extra tab below the Earth pin; the 10A unit has "15" embossed in it whereas the 15A unit has "15 N" embossed; the 15A unit has "15A" on the switch.
shows the back of the 10A unit. The colour rings on the Earth and active can be seen. Figure 4
shows the back of the 15A unit. The colour half-rings on the Earth and active can be seen. In this photo it is also possible to see the extra section on the white front plate that mates with the tab on the black plastic. Figure 5
shows the 10A GPO with the front plate removed. Figure 6
shows the 15A GPO with the front plate removed.
It seems that the moulding used in this particular sample of a 15A GPO is also designed to accommodate a neon indicator (maybe this is what the embossed "N" means?).
It is not obvious in the photos, but the Earth metal work in the 10A unit is not fixed to the black plastic and can readily be removed. Whereas in the 15A unit the Earth pin metal work seems to be fixed to the black plastic by slight flaring of the screw connector.
The two plastic sections in the 10A and 15A GPOs are different. The front covers obviously have different size openings for the Earth pins; and the 15A unit also has the extra tab below the Earth pin. It is hard to tell if the other differences are functional. For example the 15A unit used here has provision of a neon indicator but the 10A unit doesn't. Both units are available with a neon indicator. Also, the differences in the way the Earth and active colours are applied seems to suggest that these units maybe from a different manufacturing batch, or that perhaps the design has been changed at some stage.
The size of the Earth contacts/wipers seem to be identical in both units. There doesn't seem to be any difference in the contacts of the Earth socket in a 10A GPO and the Earth in a 15A GPO.
Figure 7 There doesn't appear to be any difference in the between the switch mechanisms of the 10A and 15A GPOs.
shows the switch removed from the 15A GPO.
shows the 10A GPO with the switch mechanism removed.
Figure 9 The "rocker" plate of the switches can be seem near the bodies.
shows the 15A GPO with the switch mechanism removed.
Not shown in the photos, but the "rocker" plates have a slot indentation stamped into the other sides that is part of the locating mechanism. The size of the plates was measured to be:
10A unit: 13.02 x 6.32 x 1.22 (mm)It is hard to tell if the slight size differences are due to manufacturing tolerances; units being of different batches; or caused by slight distortions due to stamping the slot in the other side.
15A unit: 12.97 x 6.40 x 1.26 (mm)
Looking closer at the active (a pun, but quite appropriate in this case) components.
Figure 10The "switched active" of the 15A GPO also can be removed the same way as shown in Figure 10.
shows the "switched active" removed from the 10A GPO.
The size of the "switched actives" of both GPOs were measured to determine if there is any differences.
shows the width of the switched-active in the 10A GPO at the narrowest part (5.88mm).
shows the thickness of the switched-active in the 10A GPO (0.68mm).
shows the width of the switched-active in the 15A GPO at the narrowest part (5.88mm).
Figure 14The size of these components seem to be identical within measurement error.
shows the thickness of the switched-active in the 15A GPO (0.67mm).
An interesting difference was noted between the switched-actives of the 10A and 15A GPOs. Looking at Figure 15 it can be seem that the top the switched actives has what looks like a deformed, or mis-stamped switch contact. The upper switched-active is from the 15A GPO.
As far as I can tell from physical inspection and measurement, the internals of the 10A single GPO seem to be functionally identical to the internals of the 15A GPO.
Does this mean that there are no differences internally between 10A GPOs and 15A GPOs? In this instance it seems there is little or no difference, but this could be because the manufacturer has decided to use 15A internals in the 10A single GPOs to reduce inventory.
Do the 10A double GPOs have lighter internals than the single GPOs? I don't know.
These posts are intended for general knowledge only. The author does not wish to imply that a 10A GPO can be used instead of the 15A GPO. There maybe differences with other brands or models. Do not use 10A GPO in place of a 15A GPO. It is illegal to do fixed electrical work in Australia unless licensed to do so.