custom part builder

[Douaa]

when i  design a custom manhole in part builder , i have a problem that when i do swap part to place the new manhole that i created instead of an old one in my network (my model), the new manhole seems quite big its even bigger than my model so what do you think i should do ? my manhole is in mm and all the part in my system is in mm but when i measure it in the system its in m .